在Go中，要跳出嵌套循環(huán)，應(yīng)使用標(biāo)籤化break語句或通過函數(shù)返回；1. 使用標(biāo)籤化break：將標(biāo)籤置於外層循環(huán)前，如OuterLoop: for {...}，在內(nèi)層循環(huán)中使用break OuterLoop即可直接退出外層循環(huán)；2. 將嵌套循環(huán)放入函數(shù)中，滿足條件時用return提前返回，從而終止所有循環(huán)；3. 避免使用標(biāo)誌變量或goto，前者冗長易錯，後者非推薦做法；正確做法是標(biāo)籤必須位於循環(huán)之前而非之後，這是Go語言中跳出多層循環(huán)的慣用方式。

In Go, there's no built-in break keyword that directly breaks out of multiple nested loops like in some other languages. However, you can break from a nested loop using labeled breaks —a feature Go supports specifically for this purpose.

Here's how to do it cleanly and effectively.

? Use Labeled Breaks to Exit Nested Loops

Go allows you to attach a label to an outer loop, and then use break with that label to exit from deep inside a nested loop.

Syntax:

 OuterLoop:
    for {
        for {
            break OuterLoop // Exits the outer for loop
        }
    }

Example:

 package main

import "fmt"

func main() {
    for i := 0; i < 3; i {
        for j := 0; j < 3; j {
            if i == 1 && j == 1 {
                break OuterLoop
            }
            fmt.Printf("i=%d, j=%d\n", i, j)
        }
    }

OuterLoop:
    fmt.Println("Exited from nested loop")
}

Wait — that won't work! The label must be placed before the loop you want to break out of , not after.

? Correct version:

 package main

import "fmt"

func main() {
OuterLoop:
    for i := 0; i < 3; i {
        for j := 0; j < 3; j {
            if i == 1 && j == 1 {
                break OuterLoop
            }
            fmt.Printf("i=%d, j=%d\n", i, j)
        }
    }
    fmt.Println("Exited from nested loop")
}

Output:

 i=0, j=0
i=0, j=1
i=0, j=2
i=1, j=0
Exited from nested loop

As soon as i == 1 and j == 1 , the break OuterLoop exits both loops immediately.

? Alternative: Use a Function with return

If you're inside a function, another clean way is to use return to exit early.

 func findValue() {
    for i := 0; i < 10; i {
        for j := 0; j < 10; j {
            if someCondition(i, j) {
                fmt.Println("Found!")
                return // Exits the function, effectively breaking all loops
            }
        }
    }
}

This is often cleaner and more readable , especially when the logic is complex.

?? Other Options (Not Recommended)

• Using a flag variable : You can set a flag and break each loop manually, but this gets messy:

   found := false
    for i := 0; i < 3; i {
        if found {
            break
        }
        for j := 0; j < 3; j {
            if i == 1 && j == 1 {
                found = true
                break
            }
            fmt.Printf("i=%d, j=%d\n", i, j)
        }
    }

  This works but is verbose and error-prone with deeper nesting.

• Goto? While goto exists in Go, don't use it just to break from loops. Labeled break is the intended solution.

---

Summary

To break from a nested loop in Go:

• ? Use labeled breaks for clean, readable control flow.
• ? Or wrap the loops in a function and use return .
• ? Avoid flag variables or goto unless absolutely necessary.

Labeled breaks are the idiomatic Go way — just remember: put the label before the outer loop , not after.

Basically, that's it — Go gives you the tools, just not the same ones as break 2 in PHP or similar.

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