突破 if 和 foreach [英] break out of if and foreach

问题描述

我有一个 foreach 循环和一个 if 语句.如果找到匹配项，我需要最终退出 foreach.

I have a foreach loop and an if statement. If a match is found i need to ultimately break out of the foreach.

foreach ($equipxml as $equip) {

    $current_device = $equip->xpath("name");
    if ($current_device[0] == $device) {

        // Found a match in the file.
        $nodeid = $equip->id;

        <break out of if and foreach here>
    }
}

推荐答案

if 不是循环结构，所以你不能打破它".

if is not a loop structure, so you cannot "break out of it".

然而，您可以通过简单地调用 break 来突破 foreach.在您的示例中，它具有预期的效果:

You can, however, break out of the foreach by simply calling break. In your example it has the desired effect:

$device = "wanted";
foreach($equipxml as $equip) {
    $current_device = $equip->xpath("name");
    if ( $current_device[0] == $device ) {
        // found a match in the file            
        $nodeid = $equip->id;

        // will leave the foreach loop and also the if statement
        break;
        some_function(); // never reached!
    }
    another_function();  // not executed after match/break
}

---

只是为了其他人偶然发现这个问题以寻求答案的完整性..

---

Just for completeness for others that stumble upon this question looking for an answer..

break 接受一个可选参数，它定义了有多少 应该打破的循环结构.示例:

break takes an optional argument, which defines how many loop structures it should break. Example:

foreach (array('1','2','3') as $a) {
    echo "$a ";
    foreach (array('3','2','1') as $b) {
        echo "$b ";
        if ($a == $b) { 
            break 2;  // this will break both foreach loops
        }
    }
    echo ". ";  // never reached!
}
echo "!";

结果输出:

1 3 2 1 ！

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