How to capture variables using golang function closure

How to use Go function closure to capture variables? Define a function parameter containing the variables to be captured. Within the function body, use the captured variables. Example: Counter Closure Cache Closure Closures are used in Go to capture variables and create flexible and reusable code.

How to use Go function closure to capture variables

A closure is a function that contains free variables, and the free variables are in the function Defined externally, but accessible within the function. In Go, closures can be created by following these steps:

1. Define a function whose arguments contain the variables to be captured.
2. In the function body, use the captured variables.

Sample code:

package main

import "fmt"

func main() {
    x := 10
    f := func() {
        // x 是一个自由变量，可以在 f 内访问
        fmt.Println(x)
    }

    // 运行闭包
    f()
}

In the above example, the f function is a closure that captures the variable x. When f is called, it prints the value of x, which is 10.

Other examples:

• Counter closure: Create a loop counter, even if the closure function has returned Can keep count.

  func counter(start int) func() int {
    x := start
    return func() int {
        x++
        return x
    }
  }

• Cache closure: Creates a function whose results are cached to improve performance.

  func cachingCalc(expensiveComputation func(int) int) func(int) int {
    cache := make(map[int]int)
    return func(x int) int {
        if v, ok := cache[x]; ok {
            return v
        }
        v = expensiveComputation(x)
        cache[x] = v
        return v
    }
  }

  Closures are a powerful tool in Go for capturing variables and creating flexible and reusable code.

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