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Slice ​

Package slice implements some functions to manipulate slice.

Source: ​

Usage: ​

go
import (
    "github.com/duke-git/lancet/v2/slice"
)
import (
    "github.com/duke-git/lancet/v2/slice"
)

Index ​

Documentation ​

AppendIfAbsent ​

If slice doesn't contain the item, append it to the slice.

Signature:

go
func AppendIfAbsent[T comparable](slice []T, item T) []T
func AppendIfAbsent[T comparable](slice []T, item T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.AppendIfAbsent([]string{"a", "b"}, "b")
    result2 := slice.AppendIfAbsent([]string{"a", "b"}, "c")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // [a b]
    // [a b c]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.AppendIfAbsent([]string{"a", "b"}, "b")
    result2 := slice.AppendIfAbsent([]string{"a", "b"}, "c")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // [a b]
    // [a b c]
}

Contain ​

Check if the target value is in the slice or not.

Signature:

go
func Contain[T comparable](slice []T, target T) bool
func Contain[T comparable](slice []T, target T) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.Contain([]string{"a", "b", "c"}, "a")
    result2 := slice.Contain([]int{1, 2, 3}, 4)

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.Contain([]string{"a", "b", "c"}, "a")
    result2 := slice.Contain([]int{1, 2, 3}, 4)

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}

ContainBy ​

returns true if predicate function return true.

Signature:

go
func ContainBy[T any](slice []T, predicate func(item T) bool) bool
func ContainBy[T any](slice []T, predicate func(item T) bool) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    type foo struct {
        A string
        B int
    }

    array1 := []foo{{A: "1", B: 1}, {A: "2", B: 2}}
    result1 := slice.ContainBy(array1, func(f foo) bool { return f.A == "1" && f.B == 1 })
    result2 := slice.ContainBy(array1, func(f foo) bool { return f.A == "2" && f.B == 1 })

    array2 := []string{"a", "b", "c"}
    result3 := slice.ContainBy(array2, func(t string) bool { return t == "a" })
    result4 := slice.ContainBy(array2, func(t string) bool { return t == "d" })

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)

    // Output:
    // true
    // false
    // true
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    type foo struct {
        A string
        B int
    }

    array1 := []foo{{A: "1", B: 1}, {A: "2", B: 2}}
    result1 := slice.ContainBy(array1, func(f foo) bool { return f.A == "1" && f.B == 1 })
    result2 := slice.ContainBy(array1, func(f foo) bool { return f.A == "2" && f.B == 1 })

    array2 := []string{"a", "b", "c"}
    result3 := slice.ContainBy(array2, func(t string) bool { return t == "a" })
    result4 := slice.ContainBy(array2, func(t string) bool { return t == "d" })

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)

    // Output:
    // true
    // false
    // true
    // false
}

ContainSubSlice ​

Check if the slice contain subslice or not.

Signature:

go
func ContainSubSlice[T comparable](slice, subSlice []T) bool
func ContainSubSlice[T comparable](slice, subSlice []T) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.ContainSubSlice([]string{"a", "b", "c"}, []string{"a", "b"})
    result2 := slice.ContainSubSlice([]string{"a", "b", "c"}, []string{"a", "d"})

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.ContainSubSlice([]string{"a", "b", "c"}, []string{"a", "b"})
    result2 := slice.ContainSubSlice([]string{"a", "b", "c"}, []string{"a", "d"})

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}

Chunk ​

Creates an slice of elements split into groups the length of `size`.

Signature:

go
func Chunk[T any](slice []T, size int) [][]T
func Chunk[T any](slice []T, size int) [][]T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    arr := []string{"a", "b", "c", "d", "e"}

    result1 := slice.Chunk(arr, 1)
    result2 := slice.Chunk(arr, 2)
    result3 := slice.Chunk(arr, 3)
    result4 := slice.Chunk(arr, 4)
    result5 := slice.Chunk(arr, 5)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)
    fmt.Println(result5)

    // Output:
    // [[a] [b] [c] [d] [e]]
    // [[a b] [c d] [e]]
    // [[a b c] [d e]]
    // [[a b c d] [e]]
    // [[a b c d e]]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    arr := []string{"a", "b", "c", "d", "e"}

    result1 := slice.Chunk(arr, 1)
    result2 := slice.Chunk(arr, 2)
    result3 := slice.Chunk(arr, 3)
    result4 := slice.Chunk(arr, 4)
    result5 := slice.Chunk(arr, 5)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)
    fmt.Println(result5)

    // Output:
    // [[a] [b] [c] [d] [e]]
    // [[a b] [c d] [e]]
    // [[a b c] [d e]]
    // [[a b c d] [e]]
    // [[a b c d e]]
}

Compact ​

Creates an slice with all falsey values removed. The values false, nil, 0, and "" are falsey.

Signature:

go
func Compact[T comparable](slice []T) []T
func Compact[T comparable](slice []T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.Compact([]int{0})
    result2 := slice.Compact([]int{0, 1, 2, 3})
    result3 := slice.Compact([]string{"", "a", "b", "0"})
    result4 := slice.Compact([]bool{false, true, true})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)

    // Output:
    // []
    // [1 2 3]
    // [a b 0]
    // [true true]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.Compact([]int{0})
    result2 := slice.Compact([]int{0, 1, 2, 3})
    result3 := slice.Compact([]string{"", "a", "b", "0"})
    result4 := slice.Compact([]bool{false, true, true})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)

    // Output:
    // []
    // [1 2 3]
    // [a b 0]
    // [true true]
}

Concat ​

Creates a new slice concatenating slice with any additional slices.

Signature:

go
func Concat[T any](slice []T, slices ...[]T) []T
func Concat[T any](slice []T, slices ...[]T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.Concat([]int{1, 2}, []int{3, 4})
    result2 := slice.Concat([]string{"a", "b"}, []string{"c"}, []string{"d"})

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // [1 2 3 4]
    // [a b c d]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.Concat([]int{1, 2}, []int{3, 4})
    result2 := slice.Concat([]string{"a", "b"}, []string{"c"}, []string{"d"})

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // [1 2 3 4]
    // [a b c d]
}

Count ​

Returns the number of occurrences of the given item in the slice.

Signature:

go
func Count[T comparable](slice []T, item T) int
func Count[T comparable](slice []T, item T) int

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 3, 4}

    result1 := slice.Count(nums, 1)
    result2 := slice.Count(nums, 3)

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 1
    // 2
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 3, 4}

    result1 := slice.Count(nums, 1)
    result2 := slice.Count(nums, 3)

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 1
    // 2
}

CountBy ​

Iterates over elements of slice with predicate function, returns the number of all matched elements.

Signature:

go
func CountBy[T any](slice []T, predicate func(index int, item T) bool) int
func CountBy[T any](slice []T, predicate func(index int, item T) bool) int

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result := slice.CountBy(nums, isEven)

    fmt.Println(result)

    // Output:
    // 2
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result := slice.CountBy(nums, isEven)

    fmt.Println(result)

    // Output:
    // 2
}

Difference ​

Creates an slice of whose element not included in the other given slice.

Signature:

go
func Difference[T comparable](slice, comparedSlice []T) []T
func Difference[T comparable](slice, comparedSlice []T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3, 4, 5}
    s2 := []int{4, 5, 6}

    result := slice.Difference(s1, s2)

    fmt.Println(result)

    // Output:
    // [1 2 3]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3, 4, 5}
    s2 := []int{4, 5, 6}

    result := slice.Difference(s1, s2)

    fmt.Println(result)

    // Output:
    // [1 2 3]
}

DifferenceBy ​

DifferenceBy accepts iteratee func which is invoked for each element of slice and values to generate the criterion by which they're compared.

Signature:

go
func DifferenceBy[T comparable](slice []T, comparedSlice []T, iteratee func(index int, item T) T) []T
func DifferenceBy[T comparable](slice []T, comparedSlice []T, iteratee func(index int, item T) T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3, 4, 5}
    s2 := []int{3, 4, 5}

    addOne := func(i int, v int) int {
        return v + 1
    }

    result := slice.DifferenceBy(s1, s2, addOne)

    fmt.Println(result)

    // Output:
    // [1 2]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3, 4, 5}
    s2 := []int{3, 4, 5}

    addOne := func(i int, v int) int {
        return v + 1
    }

    result := slice.DifferenceBy(s1, s2, addOne)

    fmt.Println(result)

    // Output:
    // [1 2]
}

DifferenceWith ​

DifferenceWith accepts comparator which is invoked to compare elements of slice to values. The order and references of result values are determined by the first slice.

Signature:

go
func DifferenceWith[T any](slice []T, comparedSlice []T, comparator func(value, otherValue T) bool) []T
func DifferenceWith[T any](slice []T, comparedSlice []T, comparator func(value, otherValue T) bool) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3, 4, 5}
    s2 := []int{4, 5, 6, 7, 8}

    isDouble := func(v1, v2 int) bool {
        return v2 == 2*v1
    }

    result := slice.DifferenceWith(s1, s2, isDouble)

    fmt.Println(result)

    // Output:
    // [1 5]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3, 4, 5}
    s2 := []int{4, 5, 6, 7, 8}

    isDouble := func(v1, v2 int) bool {
        return v2 == 2*v1
    }

    result := slice.DifferenceWith(s1, s2, isDouble)

    fmt.Println(result)

    // Output:
    // [1 5]
}

DeleteAt ​

Delete the element of slice from start index to end index - 1.

Signature:

go
func DeleteAt[T any](slice []T, start int, end ...int)
func DeleteAt[T any](slice []T, start int, end ...int)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.DeleteAt([]string{"a", "b", "c"}, -1)
    result2 := slice.DeleteAt([]string{"a", "b", "c"}, 0)
    result3 := slice.DeleteAt([]string{"a", "b", "c"}, 0, 2)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // [a b c]
    // [b c]
    // [c]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.DeleteAt([]string{"a", "b", "c"}, -1)
    result2 := slice.DeleteAt([]string{"a", "b", "c"}, 0)
    result3 := slice.DeleteAt([]string{"a", "b", "c"}, 0, 2)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // [a b c]
    // [b c]
    // [c]
}

Drop ​

Drop n elements from the start of a slice.

Signature:

go
func Drop[T any](slice []T, n int) []T
func Drop[T any](slice []T, n int) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.Drop([]string{"a", "b", "c"}, 0)
    result2 := slice.Drop([]string{"a", "b", "c"}, 1)
    result3 := slice.Drop([]string{"a", "b", "c"}, -1)
    result4 := slice.Drop([]string{"a", "b", "c"}, 4)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)

    // Output:
    // [a b c]
    // [b c]
    // [a b c]
    // []
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.Drop([]string{"a", "b", "c"}, 0)
    result2 := slice.Drop([]string{"a", "b", "c"}, 1)
    result3 := slice.Drop([]string{"a", "b", "c"}, -1)
    result4 := slice.Drop([]string{"a", "b", "c"}, 4)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)

    // Output:
    // [a b c]
    // [b c]
    // [a b c]
    // []
}

DropRight ​

Drop n elements from the end of a slice.

Signature:

go
func DropRight[T any](slice []T, n int) []T
func DropRight[T any](slice []T, n int) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.DropRight([]string{"a", "b", "c"}, 0)
    result2 := slice.DropRight([]string{"a", "b", "c"}, 1)
    result3 := slice.DropRight([]string{"a", "b", "c"}, -1)
    result4 := slice.DropRight([]string{"a", "b", "c"}, 4)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)

    // Output:
    // [a b c]
    // [a b]
    // [a b c]
    // []
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.DropRight([]string{"a", "b", "c"}, 0)
    result2 := slice.DropRight([]string{"a", "b", "c"}, 1)
    result3 := slice.DropRight([]string{"a", "b", "c"}, -1)
    result4 := slice.DropRight([]string{"a", "b", "c"}, 4)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)

    // Output:
    // [a b c]
    // [a b]
    // [a b c]
    // []
}

DropWhile ​

Drop n elements from the start of a slice while predicate function returns true.

Signature:

go
func DropWhile[T any](slice []T, predicate func(item T) bool) []T
func DropWhile[T any](slice []T, predicate func(item T) bool) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.DropWhile(numbers, func(n int) bool {
        return n != 2
    })
    result2 := slice.DropWhile(numbers, func(n int) bool {
        return true
    })
    result3 := slice.DropWhile(numbers, func(n int) bool {
        return n == 0
    })

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // [2 3 4 5]
    // []
    // [1 2 3 4 5]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.DropWhile(numbers, func(n int) bool {
        return n != 2
    })
    result2 := slice.DropWhile(numbers, func(n int) bool {
        return true
    })
    result3 := slice.DropWhile(numbers, func(n int) bool {
        return n == 0
    })

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // [2 3 4 5]
    // []
    // [1 2 3 4 5]
}

DropRightWhile ​

Drop n elements from the end of a slice while predicate function returns true.

Signature:

go
func DropRightWhile[T any](slice []T, predicate func(item T) bool) []T
func DropRightWhile[T any](slice []T, predicate func(item T) bool) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    numbers := []int{1, 2, 3, 4, 5}

    result1 := slice.DropRightWhile(numbers, func(n int) bool {
        return n != 2
    })
    result2 := slice.DropRightWhile(numbers, func(n int) bool {
        return true
    })
    result3 := slice.DropRightWhile(numbers, func(n int) bool {
        return n == 0
    })

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // [1 2]
    // []
    // [1 2 3 4 5]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    numbers := []int{1, 2, 3, 4, 5}

    result1 := slice.DropRightWhile(numbers, func(n int) bool {
        return n != 2
    })
    result2 := slice.DropRightWhile(numbers, func(n int) bool {
        return true
    })
    result3 := slice.DropRightWhile(numbers, func(n int) bool {
        return n == 0
    })

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // [1 2]
    // []
    // [1 2 3 4 5]
}

Equal ​

Check if two slices are equal: the same length and all elements' order and value are equal.

Signature:

go
func Equal[T comparable](slice1, slice2 []T) bool
func Equal[T comparable](slice1, slice2 []T) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3}
    s2 := []int{1, 2, 3}
    s3 := []int{1, 3, 2}

    result1 := slice.Equal(s1, s2)
    result2 := slice.Equal(s1, s3)

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3}
    s2 := []int{1, 2, 3}
    s3 := []int{1, 3, 2}

    result1 := slice.Equal(s1, s2)
    result2 := slice.Equal(s1, s3)

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // true
    // false
}

EqualWith ​

Check if two slices are equal with comparator func.

Signature:

go
func EqualWith[T, U any](slice1 []T, slice2 []U, comparator func(T, U) bool) bool
func EqualWith[T, U any](slice1 []T, slice2 []U, comparator func(T, U) bool) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3}
    s2 := []int{2, 4, 6}

    isDouble := func(a, b int) bool {
        return b == a*2
    }

    result := slice.EqualWith(s1, s2, isDouble)

    fmt.Println(result)

    // Output:
    // true
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    s1 := []int{1, 2, 3}
    s2 := []int{2, 4, 6}

    isDouble := func(a, b int) bool {
        return b == a*2
    }

    result := slice.EqualWith(s1, s2, isDouble)

    fmt.Println(result)

    // Output:
    // true
}

Every ​

Return true if all of the values in the slice pass the predicate function.

Signature:

go
func Every[T any](slice []T, predicate func(index int, item T) bool) bool
func Every[T any](slice []T, predicate func(index int, item T) bool) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result := slice.Every(nums, isEven)

    fmt.Println(result)

    // Output:
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result := slice.Every(nums, isEven)

    fmt.Println(result)

    // Output:
    // false
}

Filter ​

Return all elements which match the function.

Signature:

go
func Filter[T any](slice []T, predicate func(index int, item T) bool) []T
func Filter[T any](slice []T, predicate func(index int, item T) bool) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result := slice.Filter(nums, isEven)

    fmt.Println(result)

    // Output:
    // [2 4]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result := slice.Filter(nums, isEven)

    fmt.Println(result)

    // Output:
    // [2 4]
}

Find(deprecated: use FindBy) ​

Iterates over elements of slice, returning the first one that passes a truth test on function.

Signature:

go
func Find[T any](slice []T, predicate func(index int, item T) bool) (*T, bool)
func Find[T any](slice []T, predicate func(index int, item T) bool) (*T, bool)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result, ok := slice.Find(nums, isEven)

    fmt.Println(*result)
    fmt.Println(ok)

    // Output:
    // 2
    // true
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result, ok := slice.Find(nums, isEven)

    fmt.Println(*result)
    fmt.Println(ok)

    // Output:
    // 2
    // true
}

FindBy ​

Iterates over elements of slice, returning the first one that passes a truth test on predicate function.If return T is nil or zero value then no items matched the predicate func. In contrast to Find or FindLast, its return value no longer requires dereferencing.

Signature:

go
func FindBy[T any](slice []T, predicate func(index int, item T) bool) (v T, ok bool)
func FindBy[T any](slice []T, predicate func(index int, item T) bool) (v T, ok bool)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result, ok := slice.FindBy(nums, isEven)

    fmt.Println(result)
    fmt.Println(ok)

    // Output:
    // 2
    // true
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result, ok := slice.FindBy(nums, isEven)

    fmt.Println(result)
    fmt.Println(ok)

    // Output:
    // 2
    // true
}

FindLast(deprecated: use FindLastBy) ​

iterates over elements of slice from end to begin, returning the last one that passes a truth test on function.

Signature:

go
func FindLast[T any](slice []T, predicate func(index int, item T) bool) (*T, bool)
func FindLast[T any](slice []T, predicate func(index int, item T) bool) (*T, bool)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result, ok := slice.FindLast(nums, isEven)

    fmt.Println(*result)
    fmt.Println(ok)

    // Output:
    // 4
    // true
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result, ok := slice.FindLast(nums, isEven)

    fmt.Println(*result)
    fmt.Println(ok)

    // Output:
    // 4
    // true
}

FindLastBy ​

FindLastBy iterates over elements of slice, returning the last one that passes a truth test on predicate function. If return T is nil or zero value then no items matched the predicate func. In contrast to Find or FindLast, its return value no longer requires dereferencing.

Signature:

go
func FindLastBy[T any](slice []T, predicate func(index int, item T) bool) (v T, ok bool)
func FindLastBy[T any](slice []T, predicate func(index int, item T) bool) (v T, ok bool)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result, ok := slice.FindLastBy(nums, isEven)

    fmt.Println(result)
    fmt.Println(ok)

    // Output:
    // 4
    // true
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result, ok := slice.FindLastBy(nums, isEven)

    fmt.Println(result)
    fmt.Println(ok)

    // Output:
    // 4
    // true
}

Flatten ​

Flatten slice with one level.

Signature:

go
func Flatten(slice any) any
func Flatten(slice any) any

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    arrs := [][][]string{{{"a", "b"}}, {{"c", "d"}}}

    result := slice.Flatten(arrs)

    fmt.Println(result)

    // Output:
    // [[a b] [c d]]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    arrs := [][][]string{{{"a", "b"}}, {{"c", "d"}}}

    result := slice.Flatten(arrs)

    fmt.Println(result)

    // Output:
    // [[a b] [c d]]
}

FlattenDeep ​

flattens slice recursive.

Signature:

go
func FlattenDeep(slice any) any
func FlattenDeep(slice any) any

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    arrs := [][][]string{{{"a", "b"}}, {{"c", "d"}}}

    result := slice.FlattenDeep(arrs)

    fmt.Println(result)

    // Output:
    // [a b c d]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    arrs := [][][]string{{{"a", "b"}}, {{"c", "d"}}}

    result := slice.FlattenDeep(arrs)

    fmt.Println(result)

    // Output:
    // [a b c d]
}

ForEach ​

Iterates over elements of slice and invokes function for each element.

Signature:

go
func ForEach[T any](slice []T, iteratee func(index int, item T))
func ForEach[T any](slice []T, iteratee func(index int, item T))

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3}

    var result []int
    addOne := func(_ int, v int) {
        result = append(result, v+1)
    }

    slice.ForEach(nums, addOne)

    fmt.Println(result)

    // Output:
    // [2 3 4]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3}

    var result []int
    addOne := func(_ int, v int) {
        result = append(result, v+1)
    }

    slice.ForEach(nums, addOne)

    fmt.Println(result)

    // Output:
    // [2 3 4]
}

ForEachWithBreak ​

Iterates over elements of slice and invokes function for each element, when iteratee return false, will break the for each loop.

Signature:

go
func ForEachWithBreak[T any](slice []T, iteratee func(index int, item T) bool)
func ForEachWithBreak[T any](slice []T, iteratee func(index int, item T) bool)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    numbers := []int{1, 2, 3, 4, 5}

    var sum int

    slice.ForEachWithBreak(numbers, func(_, n int) bool {
        if n > 3 {
            return false
        }
        sum += n
        return true
    })

    fmt.Println(sum)

    // Output:
    // 6
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    numbers := []int{1, 2, 3, 4, 5}

    var sum int

    slice.ForEachWithBreak(numbers, func(_, n int) bool {
        if n > 3 {
            return false
        }
        sum += n
        return true
    })

    fmt.Println(sum)

    // Output:
    // 6
}

GroupBy ​

Iterates over elements of the slice, each element will be group by criteria, returns two slices.

Signature:

go
func GroupBy[T any](slice []T, groupFn func(index int, item T) bool) ([]T, []T)
func GroupBy[T any](slice []T, groupFn func(index int, item T) bool) ([]T, []T)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    even, odd := slice.GroupBy(nums, isEven)

    fmt.Println(even)
    fmt.Println(odd)

    // Output:
    // [2 4]
    // [1 3 5]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    even, odd := slice.GroupBy(nums, isEven)

    fmt.Println(even)
    fmt.Println(odd)

    // Output:
    // [2 4]
    // [1 3 5]
}

GroupWith ​

Return a map composed of keys generated from the results of running each element of slice thru iteratee.

Signature:

go
func GroupWith[T any, U comparable](slice []T, iteratee func(T) U) map[U][]T
func GroupWith[T any, U comparable](slice []T, iteratee func(T) U) map[U][]T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []float64{6.1, 4.2, 6.3}

    floor := func(num float64) float64 {
        return math.Floor(num)
    }

    result := slice.GroupWith(nums, floor) //map[float64][]float64

    fmt.Println(result)

    // Output:
    // map[4:[4.2] 6:[6.1 6.3]]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []float64{6.1, 4.2, 6.3}

    floor := func(num float64) float64 {
        return math.Floor(num)
    }

    result := slice.GroupWith(nums, floor) //map[float64][]float64

    fmt.Println(result)

    // Output:
    // map[4:[4.2] 6:[6.1 6.3]]
}

IntSlice (Deprecated: use generic feature of go1.18+ for replacement) ​

Convert interface slice to int slice.

Signature:

go
func IntSlice(slice any) []int
func IntSlice(slice any) []int

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []interface{}{1, 2, 3}

    result := slice.IntSlice(nums) //[]int{1, 2, 3}
    fmt.Println(result)

    // Output:
    // [1 2 3]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []interface{}{1, 2, 3}

    result := slice.IntSlice(nums) //[]int{1, 2, 3}
    fmt.Println(result)

    // Output:
    // [1 2 3]
}

InterfaceSlice (Deprecated: use generic feature of go1.18+ for replacement) ​

Convert value to interface slice.

Signature:

go
func InterfaceSlice(slice any) []any
func InterfaceSlice(slice any) []any

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "b", "c"}

    result := slice.InterfaceSlice(strs) //[]interface{}{"a", "b", "c"}
    fmt.Println(result)

    // Output:
    // [a b c]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "b", "c"}

    result := slice.InterfaceSlice(strs) //[]interface{}{"a", "b", "c"}
    fmt.Println(result)

    // Output:
    // [a b c]
}

Intersection ​

Creates a slice of unique values that included by all slices.

Signature:

go
func Intersection[T comparable](slices ...[]T) []T
func Intersection[T comparable](slices ...[]T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums1 := []int{1, 2, 3}
    nums2 := []int{2, 3, 4}

    result := slice.Intersection(nums1, nums2)

    fmt.Println(result)

    // Output:
    // [2 3]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums1 := []int{1, 2, 3}
    nums2 := []int{2, 3, 4}

    result := slice.Intersection(nums1, nums2)

    fmt.Println(result)

    // Output:
    // [2 3]
}

InsertAt ​

insert the element into slice at index.

Signature:

go
func InsertAt[T any](slice []T, index int, value any) []T
func InsertAt[T any](slice []T, index int, value any) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.InsertAt([]string{"a", "b", "c"}, 0, "1")
    result2 := slice.InsertAt([]string{"a", "b", "c"}, 1, "1")
    result3 := slice.InsertAt([]string{"a", "b", "c"}, 2, "1")
    result4 := slice.InsertAt([]string{"a", "b", "c"}, 3, "1")
    result5 := slice.InsertAt([]string{"a", "b", "c"}, 0, []string{"1", "2", "3"})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)
    fmt.Println(result5)

    // Output:
    // [1 a b c]
    // [a 1 b c]
    // [a b 1 c]
    // [a b c 1]
    // [1 2 3 a b c]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.InsertAt([]string{"a", "b", "c"}, 0, "1")
    result2 := slice.InsertAt([]string{"a", "b", "c"}, 1, "1")
    result3 := slice.InsertAt([]string{"a", "b", "c"}, 2, "1")
    result4 := slice.InsertAt([]string{"a", "b", "c"}, 3, "1")
    result5 := slice.InsertAt([]string{"a", "b", "c"}, 0, []string{"1", "2", "3"})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)
    fmt.Println(result5)

    // Output:
    // [1 a b c]
    // [a 1 b c]
    // [a b 1 c]
    // [a b c 1]
    // [1 2 3 a b c]
}

IndexOf ​

Returns the index at which the first occurrence of a item is found in a slice or return -1 if the item cannot be found.

Signature:

go
func IndexOf[T comparable](slice []T, item T) int
func IndexOf[T comparable](slice []T, item T) int

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "a", "b", "c"}

    result1 := slice.IndexOf(strs, "a")
    result2 := slice.IndexOf(strs, "d")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 0
    // -1
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "a", "b", "c"}

    result1 := slice.IndexOf(strs, "a")
    result2 := slice.IndexOf(strs, "d")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 0
    // -1
}

LastIndexOf ​

Returns the index at which the last occurrence of a item is found in a slice or return -1 if the item cannot be found.

Signature:

go
func LastIndexOf[T comparable](slice []T, item T) int
func LastIndexOf[T comparable](slice []T, item T) int

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "a", "b", "c"}

    result1 := slice.LastIndexOf(strs, "a")
    result2 := slice.LastIndexOf(strs, "d")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 1
    // -1
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "a", "b", "c"}

    result1 := slice.LastIndexOf(strs, "a")
    result2 := slice.LastIndexOf(strs, "d")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 1
    // -1
}

Map ​

Creates an slice of values by running each element in slice thru function.

Signature:

go
func Map[T any, U any](slice []T, iteratee func(index int, item T) U) []U
func Map[T any, U any](slice []T, iteratee func(index int, item T) U) []U

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3}

    addOne := func(_ int, v int) int {
        return v + 1
    }

    result := slice.Map(nums, addOne)

    fmt.Println(result)

    // Output:
    // [2 3 4]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3}

    addOne := func(_ int, v int) int {
        return v + 1
    }

    result := slice.Map(nums, addOne)

    fmt.Println(result)

    // Output:
    // [2 3 4]
}

FilterMap ​

Returns a slice which apply both filtering and mapping to the given slice. iteratee callback function should returntwo values: 1, mapping result. 2, whether the result element should be included or not.

Signature:

go
func FilterMap[T any, U any](slice []T, iteratee func(index int, item T) (U, bool)) []U
func FilterMap[T any, U any](slice []T, iteratee func(index int, item T) (U, bool)) []U

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    getEvenNumStr := func(i, num int) (string, bool) {
        if num%2 == 0 {
            return strconv.FormatInt(int64(num), 10), true
        }
        return "", false
    }

    result := slice.FilterMap(nums, getEvenNumStr)

    fmt.Printf("%#v", result)

    // Output:
    // []string{"2", "4"}
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    getEvenNumStr := func(i, num int) (string, bool) {
        if num%2 == 0 {
            return strconv.FormatInt(int64(num), 10), true
        }
        return "", false
    }

    result := slice.FilterMap(nums, getEvenNumStr)

    fmt.Printf("%#v", result)

    // Output:
    // []string{"2", "4"}
}

FlatMap ​

Manipulates a slice and transforms and flattens it to a slice of another type.

Signature:

go
func FlatMap[T any, U any](slice []T, iteratee func(index int, item T) []U) []U
func FlatMap[T any, U any](slice []T, iteratee func(index int, item T) []U) []U

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4}

    result := slice.FlatMap(nums, func(i int, num int) []string {
        s := "hi-" + strconv.FormatInt(int64(num), 10)
        return []string{s}
    })

    fmt.Printf("%#v", result)

    // Output:
    // []string{"hi-1", "hi-2", "hi-3", "hi-4"}
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4}

    result := slice.FlatMap(nums, func(i int, num int) []string {
        s := "hi-" + strconv.FormatInt(int64(num), 10)
        return []string{s}
    })

    fmt.Printf("%#v", result)

    // Output:
    // []string{"hi-1", "hi-2", "hi-3", "hi-4"}
}

Merge ​

Merge all given slices into one slice.

Signature:

go
func Merge[T any](slices ...[]T) []T
func Merge[T any](slices ...[]T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums1 := []int{1, 2, 3}
    nums2 := []int{3, 4}

    result := slice.Merge(nums1, nums2)

    fmt.Println(result)

    // Output:
    // [1 2 3 3 4]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums1 := []int{1, 2, 3}
    nums2 := []int{3, 4}

    result := slice.Merge(nums1, nums2)

    fmt.Println(result)

    // Output:
    // [1 2 3 3 4]
}

Reverse ​

Reverse the elements order in slice.

Signature:

go
func Reverse[T any](slice []T)
func Reverse[T any](slice []T)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "b", "c", "d"}

    slice.Reverse(strs)

    fmt.Println(strs)

    // Output:
    // [d c b a]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "b", "c", "d"}

    slice.Reverse(strs)

    fmt.Println(strs)

    // Output:
    // [d c b a]
}

Reduce ​

Reduce slice.(Deprecated: use ReduceBy)

Signature:

go
func Reduce[T any](slice []T, iteratee func(index int, item1, item2 T) T, initial T) T
func Reduce[T any](slice []T, iteratee func(index int, item1, item2 T) T, initial T) T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3}

    sum := func(_ int, v1, v2 int) int {
        return v1 + v2
    }

    result := slice.Reduce(nums, sum, 0)

    fmt.Println(result)

    // Output:
    // 6
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3}

    sum := func(_ int, v1, v2 int) int {
        return v1 + v2
    }

    result := slice.Reduce(nums, sum, 0)

    fmt.Println(result)

    // Output:
    // 6
}

ReduceBy ​

Produces a value from slice by accumulating the result of each element as passed through the reducer function.

Signature:

go
func ReduceBy[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U
func ReduceBy[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.ReduceBy([]int{1, 2, 3, 4}, 0, func(_ int, item int, agg int) int {
        return agg + item
    })

    result2 := slice.ReduceBy([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
        return agg + fmt.Sprintf("%v", item)
    })

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 10
    // 1234
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.ReduceBy([]int{1, 2, 3, 4}, 0, func(_ int, item int, agg int) int {
        return agg + item
    })

    result2 := slice.ReduceBy([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
        return agg + fmt.Sprintf("%v", item)
    })

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 10
    // 1234
}

ReduceRight ​

ReduceRight is like ReduceBy, but it iterates over elements of slice from right to left.

Signature:

go
func ReduceRight[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U
func ReduceRight[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.ReduceRight([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
        return agg + fmt.Sprintf("%v", item)
    })

    fmt.Println(result)

    // Output:
    // 4321
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.ReduceRight([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
        return agg + fmt.Sprintf("%v", item)
    })

    fmt.Println(result)

    // Output:
    // 4321
}

Replace ​

Returns a copy of the slice with the first n non-overlapping instances of old replaced by new.

Signature:

go
func Replace[T comparable](slice []T, old T, new T, n int) []T
func Replace[T comparable](slice []T, old T, new T, n int) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "b", "c", "a"}

    result1 := slice.Replace(strs, "a", "x", 0)
    result2 := slice.Replace(strs, "a", "x", 1)
    result3 := slice.Replace(strs, "a", "x", 2)
    result4 := slice.Replace(strs, "a", "x", 3)
    result5 := slice.Replace(strs, "a", "x", -1)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)
    fmt.Println(result5)

    // Output:
    // [a b c a]
    // [x b c a]
    // [x b c x]
    // [x b c x]
    // [x b c x]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []string{"a", "b", "c", "a"}

    result1 := slice.Replace(strs, "a", "x", 0)
    result2 := slice.Replace(strs, "a", "x", 1)
    result3 := slice.Replace(strs, "a", "x", 2)
    result4 := slice.Replace(strs, "a", "x", 3)
    result5 := slice.Replace(strs, "a", "x", -1)

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)
    fmt.Println(result5)

    // Output:
    // [a b c a]
    // [x b c a]
    // [x b c x]
    // [x b c x]
    // [x b c x]
}

ReplaceAll ​

Returns a copy of the slice with the first n non-overlapping instances of old replaced by new.

Signature:

go
func ReplaceAll[T comparable](slice []T, old T, new T) []T
func ReplaceAll[T comparable](slice []T, old T, new T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.ReplaceAll([]string{"a", "b", "c", "a"}, "a", "x")

    fmt.Println(result)

    // Output:
    // [x b c x]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.ReplaceAll([]string{"a", "b", "c", "a"}, "a", "x")

    fmt.Println(result)

    // Output:
    // [x b c x]
}

Repeat ​

Creates a slice with length n whose elements are passed param item.

Signature:

go
func Repeat[T any](item T, n int) []T
func Repeat[T any](item T, n int) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.Repeat("a", 3)

    fmt.Println(result)

    // Output:
    // [a a a]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.Repeat("a", 3)

    fmt.Println(result)

    // Output:
    // [a a a]
}

Shuffle ​

Creates an slice of shuffled values.

Signature:

go
func Shuffle[T any](slice []T) []T
func Shuffle[T any](slice []T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}
    result := slice.Shuffle(nums)

    fmt.Println(res)

    // Output:
    // [3 1 5 4 2] (random order)
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}
    result := slice.Shuffle(nums)

    fmt.Println(res)

    // Output:
    // [3 1 5 4 2] (random order)
}

IsAscending ​

Checks if a slice is ascending order.

Signature:

go
func IsAscending[T constraints.Ordered](slice []T) bool
func IsAscending[T constraints.Ordered](slice []T) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.IsAscending([]int{1, 2, 3, 4, 5})
    result2 := slice.IsAscending([]int{5, 4, 3, 2, 1})
    result3 := slice.IsAscending([]int{2, 1, 3, 4, 5})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // true
    // false
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.IsAscending([]int{1, 2, 3, 4, 5})
    result2 := slice.IsAscending([]int{5, 4, 3, 2, 1})
    result3 := slice.IsAscending([]int{2, 1, 3, 4, 5})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // true
    // false
    // false
}

IsDescending ​

Checks if a slice is descending order.

Signature:

go
func IsDescending[T constraints.Ordered](slice []T) bool
func IsDescending[T constraints.Ordered](slice []T) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.IsDescending([]int{5, 4, 3, 2, 1})
    result2 := slice.IsDescending([]int{1, 2, 3, 4, 5})
    result3 := slice.IsDescending([]int{2, 1, 3, 4, 5})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // true
    // false
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.IsDescending([]int{5, 4, 3, 2, 1})
    result2 := slice.IsDescending([]int{1, 2, 3, 4, 5})
    result3 := slice.IsDescending([]int{2, 1, 3, 4, 5})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // true
    // false
    // false
}

IsSorted ​

Checks if a slice is sorted (ascending or descending).

Signature:

go
func IsSorted[T constraints.Ordered](slice []T) bool
func IsSorted[T constraints.Ordered](slice []T) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.IsSorted([]int{5, 4, 3, 2, 1})
    result2 := slice.IsSorted([]int{1, 2, 3, 4, 5})
    result3 := slice.IsSorted([]int{2, 1, 3, 4, 5})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // true
    // true
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.IsSorted([]int{5, 4, 3, 2, 1})
    result2 := slice.IsSorted([]int{1, 2, 3, 4, 5})
    result3 := slice.IsSorted([]int{2, 1, 3, 4, 5})

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // true
    // true
    // false
}

IsSortedByKey ​

Checks if a slice is sorted by iteratee function.

Signature:

go
func IsSortedByKey[T any, K constraints.Ordered](slice []T, iteratee func(item T) K) bool
func IsSortedByKey[T any, K constraints.Ordered](slice []T, iteratee func(item T) K) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.IsSortedByKey([]string{"a", "ab", "abc"}, func(s string) int {
        return len(s)
    })
    result2 := slice.IsSortedByKey([]string{"abc", "ab", "a"}, func(s string) int {
        return len(s)
    })
    result3 := slice.IsSortedByKey([]string{"abc", "a", "ab"}, func(s string) int {
        return len(s)
    })

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // true
    // true
    // false
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.IsSortedByKey([]string{"a", "ab", "abc"}, func(s string) int {
        return len(s)
    })
    result2 := slice.IsSortedByKey([]string{"abc", "ab", "a"}, func(s string) int {
        return len(s)
    })
    result3 := slice.IsSortedByKey([]string{"abc", "a", "ab"}, func(s string) int {
        return len(s)
    })

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)

    // Output:
    // true
    // true
    // false
}

Sort ​

Sorts a slice of any ordered type(number or string), use quick sort algrithm. Default sort order is ascending (asc), if want descending order, set param `sortOrder` to `desc`. Ordered type: number(all ints uints floats) or string.

Signature:

go
func Sort[T constraints.Ordered](slice []T, sortOrder ...string)
func Sort[T constraints.Ordered](slice []T, sortOrder ...string)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    numbers := []int{1, 4, 3, 2, 5}

    slice.Sort(numbers)
    fmt.Println(numbers) // [1 2 3 4 5]

    slice.Sort(numbers, "desc")
    fmt.Println(numbers) // [5 4 3 2 1]

    strings := []string{"a", "d", "c", "b", "e"}

    slice.Sort(strings)
    fmt.Println(strings) //[a b c d e}

    slice.Sort(strings, "desc")
    fmt.Println(strings) //[e d c b a]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    numbers := []int{1, 4, 3, 2, 5}

    slice.Sort(numbers)
    fmt.Println(numbers) // [1 2 3 4 5]

    slice.Sort(numbers, "desc")
    fmt.Println(numbers) // [5 4 3 2 1]

    strings := []string{"a", "d", "c", "b", "e"}

    slice.Sort(strings)
    fmt.Println(strings) //[a b c d e}

    slice.Sort(strings, "desc")
    fmt.Println(strings) //[e d c b a]
}

SortBy ​

Sorts the slice in ascending order as determined by the less function. This sort is not guaranteed to be stable.

Signature:

go
func SortBy[T any](slice []T, less func(a, b T) bool)
func SortBy[T any](slice []T, less func(a, b T) bool)

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    numbers := []int{1, 4, 3, 2, 5}

    slice.SortBy(numbers, func(a, b int) bool {
        return a < b
    })
    fmt.Println(numbers) // [1 2 3 4 5]

    type User struct {
        Name string
        Age  uint
    }

    users := []User{
        {Name: "a", Age: 21},
        {Name: "b", Age: 15},
        {Name: "c", Age: 100}}

    slice.SortBy(users, func(a, b User) bool {
        return a.Age < b.Age
    })

    fmt.Printf("sort users by age: %v", users)

    // output
    // [{b 15} {a 21} {c 100}]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    numbers := []int{1, 4, 3, 2, 5}

    slice.SortBy(numbers, func(a, b int) bool {
        return a < b
    })
    fmt.Println(numbers) // [1 2 3 4 5]

    type User struct {
        Name string
        Age  uint
    }

    users := []User{
        {Name: "a", Age: 21},
        {Name: "b", Age: 15},
        {Name: "c", Age: 100}}

    slice.SortBy(users, func(a, b User) bool {
        return a.Age < b.Age
    })

    fmt.Printf("sort users by age: %v", users)

    // output
    // [{b 15} {a 21} {c 100}]
}

SortByField (Deprecated: use Sort and SortBy for replacement) ​

Sort struct slice by field. Slice element should be struct, field type should be int, uint, string, or bool. Default sort type is ascending (asc), if descending order, set sortType to desc.

Signature:

go
func SortByField(slice any, field string, sortType ...string) error
func SortByField(slice any, field string, sortType ...string) error

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    type User struct {
        Name string
        Age  uint
    }

    users := []User{
        {Name: "a", Age: 21},
        {Name: "b", Age: 15},
        {Name: "c", Age: 100}}

    err := slice.SortByField(users, "Age", "desc")
    if err != nil {
        return
    }

    fmt.Println(users)

    // Output:
    // [{c 100} {a 21} {b 15}]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    type User struct {
        Name string
        Age  uint
    }

    users := []User{
        {Name: "a", Age: 21},
        {Name: "b", Age: 15},
        {Name: "c", Age: 100}}

    err := slice.SortByField(users, "Age", "desc")
    if err != nil {
        return
    }

    fmt.Println(users)

    // Output:
    // [{c 100} {a 21} {b 15}]
}

Some ​

Return true if any of the values in the list pass the predicate function.

Signature:

go
func Some[T any](slice []T, predicate func(index int, item T) bool) bool
func Some[T any](slice []T, predicate func(index int, item T) bool) bool

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result := slice.Some(nums, isEven)

    fmt.Println(result)

    // Output:
    // true
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 5}

    isEven := func(i, num int) bool {
        return num%2 == 0
    }

    result := slice.Some(nums, isEven)

    fmt.Println(result)

    // Output:
    // true
}

StringSlice (Deprecated: use generic feature of go1.18+ for replacement) ​

Convert interface slice to string slice.

Signature:

go
func StringSlice(slice any) []string
func StringSlice(slice any) []string

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []interface{}{"a", "b", "c"}

    result := slice.StringSlice(strs) //[]string{"a", "b", "c"}
    fmt.Println(result)

    // Output:
    // [a b c]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    strs := []interface{}{"a", "b", "c"}

    result := slice.StringSlice(strs) //[]string{"a", "b", "c"}
    fmt.Println(result)

    // Output:
    // [a b c]
}

SymmetricDifference ​

Create a slice whose element is in given slices, but not in both slices.

Signature:

go
func SymmetricDifference[T comparable](slices ...[]T) []T
func SymmetricDifference[T comparable](slices ...[]T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums1 := []int{1, 2, 3}
    nums2 := []int{1, 2, 4}

    result := slice.SymmetricDifference(nums1, nums2)

    fmt.Println(result)

    // Output:
    // [3 4]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums1 := []int{1, 2, 3}
    nums2 := []int{1, 2, 4}

    result := slice.SymmetricDifference(nums1, nums2)

    fmt.Println(result)

    // Output:
    // [3 4]
}

ToSlice ​

Creates a slice of give items.

Signature:

go
func ToSlice[T any](items ...T) []T
func ToSlice[T any](items ...T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.ToSlice("a", "b", "c")

    fmt.Println(result)

    // Output:
    // [a b c]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.ToSlice("a", "b", "c")

    fmt.Println(result)

    // Output:
    // [a b c]
}

ToSlicePointer ​

Returns a pointer to the slices of a variable parameter transformation

Signature:

go
func ToSlicePointer[T any](items ...T) []*T
func ToSlicePointer[T any](items ...T) []*T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    str1 := "a"
    str2 := "b"

    result := slice.ToSlicePointer(str1, str2)

    expect := []*string{&str1, &str2}

    isEqual := reflect.DeepEqual(result, expect)

    fmt.Println(isEqual)

    // Output:
    // true
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    str1 := "a"
    str2 := "b"

    result := slice.ToSlicePointer(str1, str2)

    expect := []*string{&str1, &str2}

    isEqual := reflect.DeepEqual(result, expect)

    fmt.Println(isEqual)

    // Output:
    // true
}

Unique ​

Remove duplicate elements in slice.

Signature:

go
func Unique[T comparable](slice []T) []T
func Unique[T comparable](slice []T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.Unique([]string{"a", "a", "b"})
    fmt.Println(result)

    // Output:
    // [a b]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.Unique([]string{"a", "a", "b"})
    fmt.Println(result)

    // Output:
    // [a b]
}

UniqueBy ​

Call iteratee func with every item of slice, then remove duplicated.

Signature:

go
func UniqueBy[T comparable](slice []T, iteratee func(item T) T) []T
func UniqueBy[T comparable](slice []T, iteratee func(item T) T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5, 6}
    result := slice.UniqueBy(nums, func(val int) int {
        return val % 3
    })

    fmt.Println(result)

    // Output:
    // [1 2 0]
}
import (
    "fmt"
    "github.com/duke-git/lancet/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5, 6}
    result := slice.UniqueBy(nums, func(val int) int {
        return val % 3
    })

    fmt.Println(result)

    // Output:
    // [1 2 0]
}

Union ​

Creates a slice of unique values, in order, from all given slices. using == for equality comparisons.

Signature:

go
func Union[T comparable](slices ...[]T) []T
func Union[T comparable](slices ...[]T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums1 := []int{1, 3, 4, 6}
    nums2 := []int{1, 2, 5, 6}

    result := slice.Union(nums1, nums2)

    fmt.Println(result)

    // Output:
    // [1 3 4 6 2 5]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums1 := []int{1, 3, 4, 6}
    nums2 := []int{1, 2, 5, 6}

    result := slice.Union(nums1, nums2)

    fmt.Println(result)

    // Output:
    // [1 3 4 6 2 5]
}

UnionBy ​

UnionBy is like Union, what's more it accepts iteratee which is invoked for each element of each slice.

Signature:

go
func UnionBy[T any, V comparable](predicate func(item T) V, slices ...[]T) []T
func UnionBy[T any, V comparable](predicate func(item T) V, slices ...[]T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4}

    divideTwo := func(n int) int {
        return n / 2
    }
    result := slice.UnionBy(divideTwo, nums)

    fmt.Println(result)

    // Output:
    // [1 2 4]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4}

    divideTwo := func(n int) int {
        return n / 2
    }
    result := slice.UnionBy(divideTwo, nums)

    fmt.Println(result)

    // Output:
    // [1 2 4]
}

UpdateAt ​

Update the slice element at index. if param index < 0 or index <= len(slice), will return error.

Signature:

go
func UpdateAt[T any](slice []T, index int, value T) []T
func UpdateAt[T any](slice []T, index int, value T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.UpdateAt([]string{"a", "b", "c"}, -1, "1")
    result2 := slice.UpdateAt([]string{"a", "b", "c"}, 0, "1")
    result3 := slice.UpdateAt([]string{"a", "b", "c"}, 1, "1")
    result4 := slice.UpdateAt([]string{"a", "b", "c"}, 2, "1")
    result5 := slice.UpdateAt([]string{"a", "b", "c"}, 3, "1")

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)
    fmt.Println(result5)

    // Output:
    // [a b c]
    // [1 b c]
    // [a 1 c]
    // [a b 1]
    // [a b c]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result1 := slice.UpdateAt([]string{"a", "b", "c"}, -1, "1")
    result2 := slice.UpdateAt([]string{"a", "b", "c"}, 0, "1")
    result3 := slice.UpdateAt([]string{"a", "b", "c"}, 1, "1")
    result4 := slice.UpdateAt([]string{"a", "b", "c"}, 2, "1")
    result5 := slice.UpdateAt([]string{"a", "b", "c"}, 3, "1")

    fmt.Println(result1)
    fmt.Println(result2)
    fmt.Println(result3)
    fmt.Println(result4)
    fmt.Println(result5)

    // Output:
    // [a b c]
    // [1 b c]
    // [a 1 c]
    // [a b 1]
    // [a b c]
}

Without ​

Creates a slice excluding all given items.

Signature:

go
func Without[T comparable](slice []T, items ...T) []T
func Without[T comparable](slice []T, items ...T) []T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.Without([]int{1, 2, 3, 4}, 1, 2)

    fmt.Println(result)

    // Output:
    // [3 4]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.Without([]int{1, 2, 3, 4}, 1, 2)

    fmt.Println(result)

    // Output:
    // [3 4]
}

KeyBy ​

Converts a slice to a map based on a callback function.

Signature:

go
func KeyBy[T any, U comparable](slice []T, iteratee func(item T) U) map[U]T
func KeyBy[T any, U comparable](slice []T, iteratee func(item T) U) map[U]T

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.KeyBy([]string{"a", "ab", "abc"}, func(str string) int {
        return len(str)
    })

    fmt.Println(result)

    // Output:
    // map[1:a 2:ab 3:abc]
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    result := slice.KeyBy([]string{"a", "ab", "abc"}, func(str string) int {
        return len(str)
    })

    fmt.Println(result)

    // Output:
    // map[1:a 2:ab 3:abc]
}

Join ​

Join the slice item with specify separator.

Signature:

go
func Join[T any](s []T, separator string) string
func Join[T any](s []T, separator string) string

Example:Run

go
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    result1 := slice.Join(nums, ",")
    result2 := slice.Join(nums, "-")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 1,2,3,4,5
    // 1-2-3-4-5
}
import (
    "fmt"
    "github.com/duke-git/lancet/v2/slice"
)

func main() {
    nums := []int{1, 2, 3, 4, 5}

    result1 := slice.Join(nums, ",")
    result2 := slice.Join(nums, "-")

    fmt.Println(result1)
    fmt.Println(result2)

    // Output:
    // 1,2,3,4,5
    // 1-2-3-4-5
}

Released under the MIT License.

Copyright © 2023-present Duke Du