我怎樣才能擺脫一個以上的for回圈？[復制]

此帖已于6 天前編輯并提交審核。

我有一個代碼

loop1:
    for(j=0;j<players.x.length;j  ){
      //someting
loop2:
      for(k=0;k<tankmain[players.type[j]].tankbottom.size.length;k  ){
        //someting else
loop3:
        for(i=0;i<darts.x.length;i  ){  
          if(hit){
           //something
             break loop1;
             break loop2;
             break loop3;
    }
              
            }}}

    

但無論我如何定位它，最后兩個中斷回圈都變灰了

uj5u.com熱心網友回復：

您將三個休息時間放在一起。但是當你在回圈中遇到第一個中斷時，你已經離開了回圈，因此其他兩個不會被呼叫。有關一種可能的解決方案，請參見下面的示例。

let loop1 = [1,2,3,4,5,6,7,8];
let loop2 = [10,11,12,13,14,15];
let loop3 = [50,51,52,53,54,55];

let breakLoop1 = false;
let breakLoop2 = false;
let hit = false;

for(j = 0; j < loop1.length; j  ){
    console.log(`${j} from loop1`);
        //someting
        for(k = 0; k < loop2.length; k  ){
            console.log(`${k} from loop2`);
            //someting else
            for(i = 0; i < loop3.length; i  ){  
                console.log(`${i} from loop3`);
        
                if(i == 2) hit = true;

                    if(hit) {
                        //something
                        breakLoop1 = true;
                        breakLoop2 = true;
                        console.log("leaving loop 3");
                        break; //break loop3
                    } 
            }
            
            //break inside loop2
            if(breakLoop2) {
                console.log("leaving loop 2");
                break;  
            }
        }
        
        //break inside loop1
        if(breakLoop1) {
            console.log("leaving loop 1");
            break;  
        }
}

uj5u.com熱心網友回復：

嘗試使用標志變數方法，因為將標志變數設定為 False 是打破多個回圈的另一種方法。在退出內部回圈之前，可以將變數設定為 True。在內回圈之后，外回圈中必須有一個 if 塊。

示例代碼：

def elementInArray(arr, x):
    flag = False  # Defining the flag variable
 
    # Iterating through all
    # lists present in arr:
    for i in arr:
       
        # Iterating through all the elements
        # of each of the nested lists in arr:
        for j in i:
 
            # Checking if any element in the
            # nested list is equal to x
            # and assigning True value to
            # flag if the condition is met
            # else printing the element j:
            if j == x:
                flag = True
                print('Element found')
                break
            else:
                print(j)
                 
        # If the inner loop terminates due to
        # the break statement and flag is True
        # then the following if block will
        # be executed and the break statement in it
        # will also terminate the outer loop. Else,
        # the outer loop will continue:
        if flag == True:
            break
 
 
# Driver Code:
arr = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
x = 4
elementInArray(arr, x)

uj5u.com熱心網友回復：

您可以使用標簽：

// Mark this loop, name it "outerLoop";
outerLoop: while (1) {
    while(1) {
        while(1) {
             if (condition) {
                 // break out of the specific loop "outerLoop". Works with continue too
                 break outerLoop;
             }
        }
    }
}

有關更多資訊，請參閱https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/label

標籤：javascript 循环 for循环

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