lancet/docs/mathutil.md

Mathutil

Package mathutil implements some functions for math calculation.

Source:

• https://github.com/duke-git/lancet/blob/main/mathutil/mathutil.go

Example:

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

Index

• Average
• Exponent
• Fibonacci
• Factorial
• Max
• MaxBy
• Min
• MinBy
• Percent
• RoundToFloat
• RoundToString
• TruncRound
• Range
• RangeWithStep
• AngleToRadian
• RadianToAngle
• PointDistance

Documentation

Average

Return average value of numbers. Maybe call RoundToFloat to round result.

Signature:

func Average[T constraints.Integer | constraints.Float](numbers ...T) T

Example:

package main

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

func main() {
    result1 := mathutil.Average(1, 2)

    avg := mathutil.Average(1.2, 1.4)
    result2 := mathutil.RoundToFloat(avg, 1)

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

    // Output:
    // 1
    // 1.3
}

Exponent

Calculate x to the nth power.

Signature:

func Exponent(x, n int64) int64

Example:

package main

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

func main() {
    result1 := mathutil.Exponent(10, 0)
    result2 := mathutil.Exponent(10, 1)
    result3 := mathutil.Exponent(10, 2)

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

    // Output:
    // 1
    // 10
    // 100
}

Fibonacci

Calculate the nth number of fibonacci sequence.

Signature:

func Fibonacci(first, second, n int) int

Example:

package main

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

func main() {
    result1 := mathutil.Fibonacci(1, 1, 1)
    result2 := mathutil.Fibonacci(1, 1, 2)
    result3 := mathutil.Fibonacci(1, 1, 5)

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

    // Output:
    // 1
    // 1
    // 5
}

Factorial

Calculate the factorial of x.

Signature:

func Factorial(x uint) uint

Example:

package main

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

func main() {
    result1 := mathutil.Factorial(1)
    result2 := mathutil.Factorial(2)
    result3 := mathutil.Factorial(3)

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

    // Output:
    // 1
    // 2
    // 6
}

Max

Return max value of numbers.

Signature:

func Max[T constraints.Integer | constraints.Float](numbers ...T) T

Example:

package main

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

func main() {
    result1 := mathutil.Max(1, 2, 3)
    result2 := mathutil.Max(1.2, 1.4, 1.1, 1.4)

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

    // Output:
    // 3
    // 1.4
}

MaxBy

Return the maximum value of a slice using the given comparator function.

Signature:

func MaxBy[T any](slice []T, comparator func(T, T) bool) T

Example:

package main

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

func main() {
    result1 := mathutil.MaxBy([]string{"a", "ab", "abc"}, func(v1, v2 string) bool {
        return len(v1) > len(v2)
    })

    result2 := mathutil.MaxBy([]string{"abd", "abc", "ab"}, func(v1, v2 string) bool {
        return len(v1) > len(v2)
    })

    result3 := mathutil.MaxBy([]string{}, func(v1, v2 string) bool {
        return len(v1) > len(v2)
    })

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

    // Output:
    // abc
    // abd
    //
}

Min

Return the minimum value of numbers.

Signature:

func Min[T constraints.Integer | constraints.Float](numbers ...T) T

Example:

package main

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

func main() {
    result1 := mathutil.Min(1, 2, 3)
    result2 := mathutil.Min(1.2, 1.4, 1.1, 1.4)

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

    // Output:
    // 1
    // 1.1
}

MinBy

Return the minimum value of a slice using the given comparator function.

Signature:

func MinBy[T any](slice []T, comparator func(T, T) bool) T

Example:

package main

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

func main() {
    result1 := mathutil.MinBy([]string{"a", "ab", "abc"}, func(v1, v2 string) bool {
        return len(v1) < len(v2)
    })

    result2 := mathutil.MinBy([]string{"ab", "ac", "abc"}, func(v1, v2 string) bool {
        return len(v1) < len(v2)
    })

    result3 := mathutil.MinBy([]string{}, func(v1, v2 string) bool {
        return len(v1) < len(v2)
    })

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

    // Output:
    // a
    // ab
    //
}

Percent

calculate the percentage of val to total, retain n decimal places.

Signature:

func Percent(val, total float64, n int) float64

Example:

package main

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

func main() {
    result1 := mathutil.Percent(1, 2, 2)
    result2 := mathutil.Percent(0.1, 0.3, 2)

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

    // Output:
    // 0.5
    // 0.33
}

RoundToFloat

Round float up to n decimal places.

Signature:

func RoundToFloat(x float64, n int) float64

Example:

package main

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

func main() {
    result1 := mathutil.RoundToFloat(0.124, 2)
    result2 := mathutil.RoundToFloat(0.125, 2)
    result3 := mathutil.RoundToFloat(0.125, 3)

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

    // Output:
    // 0.12
    // 0.13
    // 0.125
}

RoundToString

Round float up to n decimal places. will return string.

Signature:

func RoundToString(x float64, n int) string

Example:

package main

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

func main() {
    result1 := mathutil.RoundToString(0.124, 2)
    result2 := mathutil.RoundToString(0.125, 2)
    result3 := mathutil.RoundToString(0.125, 3)

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

    // Output:
    // 0.12
    // 0.13
    // 0.125
}

TruncRound

Round float off n decimal places.

Signature:

func TruncRound(x float64, n int) float64

Example:

package main

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

func main() {
    result1 := mathutil.TruncRound(0.124, 2)
    result2 := mathutil.TruncRound(0.125, 2)
    result3 := mathutil.TruncRound(0.125, 3)

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

    // Output:
    // 0.12
    // 0.12
    // 0.125
}

Range

Creates a slice of numbers from start with specified count, element step is 1.

Signature:

func Range[T constraints.Integer | constraints.Float](start T, count int) []T

Example:

package main

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

func main() {
    result1 := mathutil.Range(1, 4)
    result2 := mathutil.Range(1, -4)
    result3 := mathutil.Range(-4, 4)
    result4 := mathutil.Range(1.0, 4)

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

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

RangeWithStep

Creates a slice of numbers from start to end with specified step.

Signature:

func RangeWithStep[T constraints.Integer | constraints.Float](start, end, step T) []T

Example:

package main

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

func main() {
    result1 := mathutil.RangeWithStep(1, 4, 1)
    result2 := mathutil.RangeWithStep(1, -1, 0)
    result3 := mathutil.RangeWithStep(-4, 1, 2)
    result4 := mathutil.RangeWithStep(1.0, 4.0, 1.1)

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

    // Output:
    // [1 2 3]
    // []
    // [-4 -2 0]
    // [1 2.1 3.2]
}

AngleToRadian

Converts angle value to radian value.

Signature:

func AngleToRadian(angle float64) float64

Example:

package main

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

func main() {
    result1 := mathutil.AngleToRadian(45)
    result2 := mathutil.AngleToRadian(90)
    result3 := mathutil.AngleToRadian(180)

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

    // Output:
    // 0.7853981633974483
    // 1.5707963267948966
    // 3.141592653589793
}

RadianToAngle

Converts radian value to angle value.

Signature:

func RadianToAngle(radian float64) float64

Example:

package main

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

func main() {
    result1 := mathutil.RadianToAngle(math.Pi)
    result2 := mathutil.RadianToAngle(math.Pi / 2)
    result3 := mathutil.RadianToAngle(math.Pi / 4)

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

    // Output:
    // 180
    // 90
    // 45
}

PointDistance

Caculates two points distance.

Signature:

func PointDistance(x1, y1, x2, y2 float64) float64

Example:

package main

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

func main() {
    result1 := mathutil.PointDistance(1, 1, 4, 5)

    fmt.Println(result1)

    // Output:
    // 5
}