What's the Best Way to Create Iterators in Go: Channels, Closures, or Named Types?

Creating Iterators in Go: Channels vs. Closures vs. Named Types

In Go, various approaches exist for creating iterators. One popular option is utilizing channels that resemble iterators. However, channels suffer from limitations, particularly being a push model rather than a pull model, causing potential leaks.

An idiomatic approach involves employing closures. The following example demonstrates how to create an iterator for generating even numbers:

package main

import "fmt"

func main() {
    gen := newEven()
    fmt.Println(gen())
    fmt.Println(gen())
    fmt.Println(gen())
    gen = nil // release for garbage collection
}

func newEven() func() int {
    n := 0
    return func() int {
        n += 2
        return n
    }
}

Another option is using named types with methods:

package main

import "fmt"

func main() {
    gen := even(0)
    fmt.Println(gen.next())
    fmt.Println(gen.next())
    fmt.Println(gen.next())
}

type even int

func (e *even) next() int {
    *e += 2
    return int(*e)
}

The choice between closures and named types depends on specific needs. Closures provide flexibility, while named types may offer a more structured approach.

Additionally, chaining iterators is straightforward in Go due to functions being first-class objects. The following example chains a generator for even numbers with a square function:

package main

import "fmt"

func main() {
    gen := mapInt(newEven(), square)
    fmt.Println(gen())
    fmt.Println(gen())
    fmt.Println(gen())
    gen = nil // release for garbage collection
}

type intGen func() int

func newEven() intGen {
    n := 0
    return func() int {
        n += 2
        return n
    }
}

func mapInt(g intGen, f func(int) int) intGen {
    return func() int {
        return f(g())
    }
}

func square(i int) int {
    return i * i
}

The above is the detailed content of What's the Best Way to Create Iterators in Go: Channels, Closures, or Named Types?. For more information, please follow other related articles on the PHP Chinese website!