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doc: add document for stream package

This commit is contained in:
dudaodong
2023-04-05 20:17:41 +08:00
parent 5b9b4c4344
commit c53d541a6b
4 changed files with 1822 additions and 10 deletions

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# Stream
Package stream implements a sequence of elements supporting sequential and operations. This package is an experiment to explore if stream in go can work as the way java does. it's feature is very limited.
<div STYLE="page-break-after: always;"></div>
## Source:
- [https://github.com/duke-git/lancet/blob/main/stream/stream.go](https://github.com/duke-git/lancet/blob/main/stream/stream.go)
<div STYLE="page-break-after: always;"></div>
## Usage:
```go
import (
"github.com/duke-git/lancet/v2/stream"
)
```
<div STYLE="page-break-after: always;"></div>
## Index
- [Of](#Of)
- [FromSlice](#FromSlice)
- [FromChannel](#FromChannel)
- [FromRange](#FromRange)
- [Generate](#Generate)
- [Concat](#Concat)
- [Distinct](#Distinct)
- [Filter](#Filter)
- [Map](#Map)
- [Peek](#Peek)
- [Skip](#Skip)
- [Limit](#Limit)
- [Reverse](#Reverse)
- [Range](#Range)
- [Sorted](#Sorted)
- [ForEach](#ForEach)
- [Reduce](#Reduce)
- [FindFirst](#FindFirst)
- [Max](#Max)
- [Min](#Min)
- [AllMatch](#AllMatch)
- [AnyMatch](#AnyMatch)
- [NoneMatch](#NoneMatch)
- [Count](#Count)
- [ToSlice](#ToSlice)
<div STYLE="page-break-after: always;"></div>
## Documentation
### <span id="Of">Of</span>
<p>Creates a stream whose elements are the specified values.</p>
<b>Signature:</b>
```go
func Of[T any](elems ...T) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s := stream.Of(1, 2, 3)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```
### <span id="FromSlice">FromSlice</span>
<p>Creates a stream from slice.</p>
<b>Signature:</b>
```go
func FromSlice[T any](source []T) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s := stream.FromSlice([]int{1, 2, 3})
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```
### <span id="FromChannel">FromChannel</span>
<p>Creates a stream from channel.</p>
<b>Signature:</b>
```go
func FromChannel[T any](source <-chan T) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
ch := make(chan int)
go func() {
for i := 1; i < 4; i++ {
ch <- i
}
close(ch)
}()
s := stream.FromChannel(ch)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```
### <span id="FromRange">FromRange</span>
<p>Creates a number stream from start to end. both start and end are included. [start, end]</p>
<b>Signature:</b>
```go
func FromRange[T constraints.Integer | constraints.Float](start, end, step T) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s := stream.FromRange(1, 5, 1)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3 4 5]
}
```
### <span id="Generate">Generate</span>
<p>Creates a stream where each element is generated by the provided generater function.</p>
<b>Signature:</b>
```go
func Generate[T any](generator func() func() (item T, ok bool)) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
n := 0
max := 4
generator := func() func() (int, bool) {
return func() (int, bool) {
n++
return n, n < max
}
}
s := stream.Generate(generator)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```
### <span id="Concat">Concat</span>
<p>Creates a lazily concatenated stream whose elements are all the elements of the first stream followed by all the elements of the second stream.</p>
<b>Signature:</b>
```go
func Concat[T any](a, b stream[T]) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s1 := stream.FromSlice([]int{1, 2, 3})
s2 := stream.FromSlice([]int{4, 5, 6})
s := Concat(s1, s2)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3 4 5 6]
}
```
### <span id="Distinct">Distinct</span>
<p>Creates returns a stream that removes the duplicated items. <b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Distinct() stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 2, 3, 3, 3})
distinct := original.Distinct()
data1 := original.ToSlice()
data2 := distinct.ToSlice()
fmt.Println(data1)
fmt.Println(data2)
// Output:
// [1 2 2 3 3 3]
// [1 2 3]
}
```
### <span id="Filter">Filter</span>
<p>Returns a stream consisting of the elements of this stream that match the given predicate. <b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Filter(predicate func(item T) bool) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3, 4, 5})
isEven := func(n int) bool {
return n%2 == 0
}
even := original.Filter(isEven)
fmt.Println(even.ToSlice())
// Output:
// [2 4]
}
```
### <span id="Map">Map</span>
<p>Returns a stream consisting of the elements of this stream that apply the given function to elements of stream. <b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Map(mapper func(item T) T) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
addOne := func(n int) int {
return n + 1
}
increament := original.Map(addOne)
fmt.Println(increament.ToSlice())
// Output:
// [2 3 4]
}
```
### <span id="Peek">Peek</span>
<p>Returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed from the resulting stream. <b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Peek(consumer func(item T)) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
data := []string{}
peekStream := original.Peek(func(n int) {
data = append(data, fmt.Sprint("value", n))
})
fmt.Println(original.ToSlice())
fmt.Println(peekStream.ToSlice())
fmt.Println(data)
// Output:
// [1 2 3]
// [1 2 3]
// [value1 value2 value3]
}
```
### <span id="Skip">Skip</span>
<p>Returns a stream consisting of the remaining elements of this stream after discarding the first n elements of the stream. If this stream contains fewer than n elements then an empty stream will be returned. <b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Skip(n int) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3, 4})
s1 := original.Skip(-1)
s2 := original.Skip(0)
s3 := original.Skip(1)
s4 := original.Skip(5)
fmt.Println(s1.ToSlice())
fmt.Println(s2.ToSlice())
fmt.Println(s3.ToSlice())
fmt.Println(s4.ToSlice())
// Output:
// [1 2 3 4]
// [1 2 3 4]
// [2 3 4]
// []
}
```
### <span id="Limit">Limit</span>
<p>Returns a stream consisting of the elements of this stream, truncated to be no longer than maxSize in length. <b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Limit(maxSize int) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3, 4})
s1 := original.Limit(-1)
s2 := original.Limit(0)
s3 := original.Limit(1)
s4 := original.Limit(5)
fmt.Println(s1.ToSlice())
fmt.Println(s2.ToSlice())
fmt.Println(s3.ToSlice())
fmt.Println(s4.ToSlice())
// Output:
// []
// []
// [1]
// [1 2 3 4]
}
```
### <span id="Reverse">Reverse</span>
<p>Returns a stream whose elements are reverse order of given stream. <b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Reverse() stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
reverse := original.Reverse()
fmt.Println(reverse.ToSlice())
// Output:
// [3 2 1]
}
```
### <span id="Range">Range</span>
<p>Returns a stream whose elements are in the range from start(included) to end(excluded) original stream.<b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Range(start, end int) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
s1 := original.Range(0, 0)
s2 := original.Range(0, 1)
s3 := original.Range(0, 3)
s4 := original.Range(1, 2)
fmt.Println(s1.ToSlice())
fmt.Println(s2.ToSlice())
fmt.Println(s3.ToSlice())
fmt.Println(s4.ToSlice())
// Output:
// []
// [1]
// [1 2 3]
// [2]
}
```
### <span id="Sorted">Sorted</span>
<p>Returns a stream consisting of the elements of this stream, sorted according to the provided less function.<b>Support chainable operation</b></p>
<b>Signature:</b>
```go
func (s stream[T]) Sorted(less func(a, b T) bool) stream[T]
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{4, 2, 1, 3})
sorted := original.Sorted(func(a, b int) bool { return a < b })
fmt.Println(original.ToSlice())
fmt.Println(sorted.ToSlice())
// Output:
// [4 2 1 3]
// [1 2 3 4]
}
```
### <span id="ForEach">ForEach</span>
<p>Performs an action for each element of this stream.</p>
<b>Signature:</b>
```go
func (s stream[T]) ForEach(action func(item T))
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result := 0
original.ForEach(func(item int) {
result += item
})
fmt.Println(result)
// Output:
// 6
}
```
### <span id="Reduce">Reduce</span>
<p>Performs a reduction on the elements of this stream, using an associative accumulation function, and returns an Optional describing the reduced value, if any.</p>
<b>Signature:</b>
```go
func (s stream[T]) Reduce(initial T, accumulator func(a, b T) T) T
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result := original.Reduce(0, func(a, b int) int {
return a + b
})
fmt.Println(result)
// Output:
// 6
}
```
### <span id="FindFirst">FindFirst</span>
<p>Returns the first element of this stream and true, or zero value and false if the stream is empty.</p>
<b>Signature:</b>
```go
func (s stream[T]) FindFirst() (T, bool)
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result, ok := original.FindFirst()
fmt.Println(result)
fmt.Println(ok)
// Output:
// 1
// true
}
```
### <span id="Max">Max</span>
<p>Returns the maximum element of this stream according to the provided less function. less fuction: a > b</p>
<b>Signature:</b>
```go
func (s stream[T]) Max(less func(a, b T) bool) (T, bool)
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{4, 2, 1, 3})
max, ok := original.Max(func(a, b int) bool { return a > b })
fmt.Println(max)
fmt.Println(ok)
// Output:
// 4
// true
}
```
### <span id="Min">Min</span>
<p>Returns the minimum element of this stream according to the provided less function. less fuction: a < b</p>
<b>Signature:</b>
```go
func (s stream[T]) Min(less func(a, b T) bool) (T, bool)
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{4, 2, 1, 3})
min, ok := original.Min(func(a, b int) bool { return a < b })
fmt.Println(min)
fmt.Println(ok)
// Output:
// 1
// true
}
```
### <span id="AllMatch">AllMatch</span>
<p>Returns whether all elements of this stream match the provided predicate.</p>
<b>Signature:</b>
```go
func (s stream[T]) AllMatch(predicate func(item T) bool) bool
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result1 := original.AllMatch(func(item int) bool {
return item > 0
})
result2 := original.AllMatch(func(item int) bool {
return item > 1
})
fmt.Println(result1)
fmt.Println(result2)
// Output:
// true
// false
}
```
### <span id="AnyMatch">AnyMatch</span>
<p>Returns whether any elements of this stream match the provided predicate.</p>
<b>Signature:</b>
```go
func (s stream[T]) AnyMatch(predicate func(item T) bool) bool
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result1 := original.AnyMatch(func(item int) bool {
return item > 1
})
result2 := original.AnyMatch(func(item int) bool {
return item > 3
})
fmt.Println(result1)
fmt.Println(result2)
// Output:
// true
// false
}
```
### <span id="NoneMatch">NoneMatch</span>
<p>Returns whether no elements of this stream match the provided predicate.</p>
<b>Signature:</b>
```go
func (s stream[T]) NoneMatch(predicate func(item T) bool) bool
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result1 := original.NoneMatch(func(item int) bool {
return item > 3
})
result2 := original.NoneMatch(func(item int) bool {
return item > 1
})
fmt.Println(result1)
fmt.Println(result2)
// Output:
// true
// false
}
```
### <span id="Count">Count</span>
<p>Returns the count of elements in the stream.</p>
<b>Signature:</b>
```go
func (s stream[T]) Count() int
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s1 := stream.FromSlice([]int{1, 2, 3})
s2 := stream.FromSlice([]int{})
fmt.Println(s1.Count())
fmt.Println(s2.Count())
// Output:
// 3
// 0
}
```
### <span id="ToSlice">ToSlice</span>
<p>Returns the elements in the stream.</p>
<b>Signature:</b>
```go
func (s stream[T]) ToSlice() []T
```
<b>Example:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s := stream.Of(1, 2, 3)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```

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# Strutil
Stream 实现,该包仅验证简单 go stream 实现,功能有限。
<div STYLE="page-break-after: always;"></div>
## 源码:
- [https://github.com/duke-git/lancet/blob/main/stream/stream.go](https://github.com/duke-git/lancet/blob/main/stream/stream.go)
<div STYLE="page-break-after: always;"></div>
## 用法:
```go
import (
"github.com/duke-git/lancet/v2/stream"
)
```
<div STYLE="page-break-after: always;"></div>
## 目录
- [Of](#Of)
- [FromSlice](#FromSlice)
- [FromChannel](#FromChannel)
- [FromRange](#FromRange)
- [Generate](#Generate)
- [Concat](#Concat)
- [Distinct](#Distinct)
- [Filter](#Filter)
- [Map](#Map)
- [Peek](#Peek)
- [Skip](#Skip)
- [Limit](#Limit)
- [Reverse](#Reverse)
- [Range](#Range)
- [Sorted](#Sorted)
- [ForEach](#ForEach)
- [Reduce](#Reduce)
- [FindFirst](#FindFirst)
- [Max](#Max)
- [Min](#Min)
- [AllMatch](#AllMatch)
- [AnyMatch](#AnyMatch)
- [NoneMatch](#NoneMatch)
- [Count](#Count)
- [ToSlice](#ToSlice)
<div STYLE="page-break-after: always;"></div>
## 文档
### <span id="Of">Of</span>
<p>创建元素为指定值的stream。</p>
<b>函数签名:</b>
```go
func Of[T any](elems ...T) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s := stream.Of(1, 2, 3)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```
### <span id="FromSlice">FromSlice</span>
<p>从切片创建stream。</p>
<b>函数签名:</b>
```go
func FromSlice[T any](source []T) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s := stream.FromSlice([]int{1, 2, 3})
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```
### <span id="FromChannel">FromChannel</span>
<p>从通道创建stream。</p>
<b>函数签名:</b>
```go
func FromChannel[T any](source <-chan T) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
ch := make(chan int)
go func() {
for i := 1; i < 4; i++ {
ch <- i
}
close(ch)
}()
s := stream.FromChannel(ch)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```
### <span id="FromRange">FromRange</span>
<p>指定一个范围创建stream, 范围两端点值都包括在内。</p>
<b>函数签名:</b>
```go
func FromRange[T constraints.Integer | constraints.Float](start, end, step T) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s := stream.FromRange(1, 5, 1)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3 4 5]
}
```
### <span id="Generate">Generate</span>
<p>创建一个stream其中每个元素都由提供的生成器函数生成</p>
<b>函数签名:</b>
```go
func Generate[T any](generator func() func() (item T, ok bool)) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
n := 0
max := 4
generator := func() func() (int, bool) {
return func() (int, bool) {
n++
return n, n < max
}
}
s := stream.Generate(generator)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```
### <span id="Concat">Concat</span>
<p>创建一个延迟连接stream其元素是第一个stream的所有元素后跟第二个stream的全部元素。</p>
<b>函数签名:</b>
```go
func Concat[T any](a, b stream[T]) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s1 := stream.FromSlice([]int{1, 2, 3})
s2 := stream.FromSlice([]int{4, 5, 6})
s := Concat(s1, s2)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3 4 5 6]
}
```
### <span id="Distinct">Distinct</span>
<p>创建并返回一个stream用于删除重复的项。 <b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Distinct() stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 2, 3, 3, 3})
distinct := original.Distinct()
data1 := original.ToSlice()
data2 := distinct.ToSlice()
fmt.Println(data1)
fmt.Println(data2)
// Output:
// [1 2 2 3 3 3]
// [1 2 3]
}
```
### <span id="Filter">Filter</span>
<p>返回一个通过判定函数的stream <b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Filter(predicate func(item T) bool) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3, 4, 5})
isEven := func(n int) bool {
return n%2 == 0
}
even := original.Filter(isEven)
fmt.Println(even.ToSlice())
// Output:
// [2 4]
}
```
### <span id="Map">Map</span>
<p>返回一个stream该stream由将给定函数应用于源stream元素的元素组成。<b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Map(mapper func(item T) T) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
addOne := func(n int) int {
return n + 1
}
increament := original.Map(addOne)
fmt.Println(increament.ToSlice())
// Output:
// [2 3 4]
}
```
### <span id="Peek">Peek</span>
<p>返回一个由源stream的元素组成的stream并在从生成的stream中消耗元素时对每个元素执行所提供的操作。 <b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Peek(consumer func(item T)) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
data := []string{}
peekStream := original.Peek(func(n int) {
data = append(data, fmt.Sprint("value", n))
})
fmt.Println(original.ToSlice())
fmt.Println(peekStream.ToSlice())
fmt.Println(data)
// Output:
// [1 2 3]
// [1 2 3]
// [value1 value2 value3]
}
```
### <span id="Skip">Skip</span>
<p>在丢弃stream的前n个元素后返回由源stream的其余元素组成的stream。如果此stream包含的元素少于n个则将返回一个空stream。<b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Skip(n int) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3, 4})
s1 := original.Skip(-1)
s2 := original.Skip(0)
s3 := original.Skip(1)
s4 := original.Skip(5)
fmt.Println(s1.ToSlice())
fmt.Println(s2.ToSlice())
fmt.Println(s3.ToSlice())
fmt.Println(s4.ToSlice())
// Output:
// [1 2 3 4]
// [1 2 3 4]
// [2 3 4]
// []
}
```
### <span id="Limit">Limit</span>
<p>返回由源stream的元素组成的stream该stream被截断为长度不超过maxSize。<b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Limit(maxSize int) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3, 4})
s1 := original.Limit(-1)
s2 := original.Limit(0)
s3 := original.Limit(1)
s4 := original.Limit(5)
fmt.Println(s1.ToSlice())
fmt.Println(s2.ToSlice())
fmt.Println(s3.ToSlice())
fmt.Println(s4.ToSlice())
// Output:
// []
// []
// [1]
// [1 2 3 4]
}
```
### <span id="Reverse">Reverse</span>
<p>返回元素与源stream的顺序相反的stream。<b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Reverse() stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
reverse := original.Reverse()
fmt.Println(reverse.ToSlice())
// Output:
// [3 2 1]
}
```
### <span id="Range">Range</span>
<p>返回一个stream该stream的元素在从源stream的开始包含到结束排除的范围内。<b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Range(start, end int) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
s1 := original.Range(0, 0)
s2 := original.Range(0, 1)
s3 := original.Range(0, 3)
s4 := original.Range(1, 2)
fmt.Println(s1.ToSlice())
fmt.Println(s2.ToSlice())
fmt.Println(s3.ToSlice())
fmt.Println(s4.ToSlice())
// Output:
// []
// [1]
// [1 2 3]
// [2]
}
```
### <span id="Sorted">Sorted</span>
<p>返回一个stream该stream由源stream的元素组成并根据提供的less函数进行排序。<b>支持链式操作</b></p>
<b>函数签名:</b>
```go
func (s stream[T]) Sorted(less func(a, b T) bool) stream[T]
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{4, 2, 1, 3})
sorted := original.Sorted(func(a, b int) bool { return a < b })
fmt.Println(original.ToSlice())
fmt.Println(sorted.ToSlice())
// Output:
// [4 2 1 3]
// [1 2 3 4]
}
```
### <span id="ForEach">ForEach</span>
<p>对stream的每个元素执行一个操作。</p>
<b>函数签名:</b>
```go
func (s stream[T]) ForEach(action func(item T))
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result := 0
original.ForEach(func(item int) {
result += item
})
fmt.Println(result)
// Output:
// 6
}
```
### <span id="Reduce">Reduce</span>
<p>使用关联累加函数对stream的元素执行reduce操作并reduce操作结果如果有。</p>
<b>函数签名:</b>
```go
func (s stream[T]) Reduce(initial T, accumulator func(a, b T) T) T
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result := original.Reduce(0, func(a, b int) int {
return a + b
})
fmt.Println(result)
// Output:
// 6
}
```
### <span id="FindFirst">FindFirst</span>
<p>返回此stream的第一个元素和true如果stream为空则返回零值和false。</p>
<b>函数签名:</b>
```go
func (s stream[T]) FindFirst() (T, bool)
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result, ok := original.FindFirst()
fmt.Println(result)
fmt.Println(ok)
// Output:
// 1
// true
}
```
### <span id="Max">Max</span>
<p>根据提供的less函数返回stream的最大元素。less 函数: a > b</p>
<b>函数签名:</b>
```go
func (s stream[T]) Max(less func(a, b T) bool) (T, bool)
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{4, 2, 1, 3})
max, ok := original.Max(func(a, b int) bool { return a > b })
fmt.Println(max)
fmt.Println(ok)
// Output:
// 4
// true
}
```
### <span id="Min">Min</span>
<p>根据提供的less函数返回stream的最小元素。less函数: a < b</p>
<b>函数签名:</b>
```go
func (s stream[T]) Min(less func(a, b T) bool) (T, bool)
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{4, 2, 1, 3})
min, ok := original.Min(func(a, b int) bool { return a < b })
fmt.Println(min)
fmt.Println(ok)
// Output:
// 1
// true
}
```
### <span id="AllMatch">AllMatch</span>
<p>判断stream的所有元素是否全部匹配指定判定函数。</p>
<b>函数签名:</b>
```go
func (s stream[T]) AllMatch(predicate func(item T) bool) bool
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result1 := original.AllMatch(func(item int) bool {
return item > 0
})
result2 := original.AllMatch(func(item int) bool {
return item > 1
})
fmt.Println(result1)
fmt.Println(result2)
// Output:
// true
// false
}
```
### <span id="AnyMatch">AnyMatch</span>
<p>判断stream是否包含匹配指定判定函数的元素。</p>
<b>函数签名:</b>
```go
func (s stream[T]) AnyMatch(predicate func(item T) bool) bool
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result1 := original.AnyMatch(func(item int) bool {
return item > 1
})
result2 := original.AnyMatch(func(item int) bool {
return item > 3
})
fmt.Println(result1)
fmt.Println(result2)
// Output:
// true
// false
}
```
### <span id="NoneMatch">NoneMatch</span>
<p>判断stream的元素是否全部不匹配指定的判定函数。</p>
<b>函数签名:</b>
```go
func (s stream[T]) NoneMatch(predicate func(item T) bool) bool
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
original := stream.FromSlice([]int{1, 2, 3})
result1 := original.NoneMatch(func(item int) bool {
return item > 3
})
result2 := original.NoneMatch(func(item int) bool {
return item > 1
})
fmt.Println(result1)
fmt.Println(result2)
// Output:
// true
// false
}
```
### <span id="Count">Count</span>
<p>返回stream中元素的数量。</p>
<b>函数签名:</b>
```go
func (s stream[T]) Count() int
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s1 := stream.FromSlice([]int{1, 2, 3})
s2 := stream.FromSlice([]int{})
fmt.Println(s1.Count())
fmt.Println(s2.Count())
// Output:
// 3
// 0
}
```
### <span id="ToSlice">ToSlice</span>
<p>返回stream中的元素切片。</p>
<b>函数签名:</b>
```go
func (s stream[T]) ToSlice() []T
```
<b>示例:</b>
```go
import (
"fmt"
"github.com/duke-git/lancet/v2/stream"
)
func main() {
s := stream.Of(1, 2, 3)
data := s.ToSlice()
fmt.Println(data)
// Output:
// [1 2 3]
}
```

View File

@@ -51,7 +51,7 @@ type stream[T any] struct {
source []T
}
// Of creates a stream stream whose elements are the specified values.
// Of creates a stream whose elements are the specified values.
// Play: https://go.dev/play/p/jI6_iZZuVFE
func Of[T any](elems ...T) stream[T] {
return FromSlice(elems)
@@ -268,7 +268,7 @@ func (s stream[T]) ForEach(action func(item T)) {
}
// Reduce performs a reduction on the elements of this stream, using an associative accumulation function, and returns an Optional describing the reduced value, if any.
// Play: https://go.dev/play/p/g-xkHiuIpTi
// Play: https://go.dev/play/p/6uzZjq_DJLU
func (s stream[T]) Reduce(initial T, accumulator func(a, b T) T) T {
for _, v := range s.source {
initial = accumulator(initial, v)

View File

@@ -91,11 +91,11 @@ func ExampleConcat() {
}
func ExampleStream_Distinct() {
originalStream := FromSlice([]int{1, 2, 2, 3, 3, 3})
distinctStream := originalStream.Distinct()
original := FromSlice([]int{1, 2, 2, 3, 3, 3})
distinct := original.Distinct()
data1 := originalStream.ToSlice()
data2 := distinctStream.ToSlice()
data1 := original.ToSlice()
data2 := distinct.ToSlice()
fmt.Println(data1)
fmt.Println(data2)
@@ -267,10 +267,8 @@ func ExampleStream_ForEach() {
func ExampleStream_Reduce() {
original := FromSlice([]int{1, 2, 3})
result := 0
original.ForEach(func(item int) {
result += item
result := original.Reduce(0, func(a, b int) int {
return a + b
})
fmt.Println(result)