Things you don't know about php switch-PHP Tutorial-php.cn

Things you don't know about php switch

黄舟

Release： 2023-03-11 11:20:01

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1736 people have browsed it

switchThe conventional usage is to pass a parameter and compare it with the case one by one;

switch (variable) {
    case &#39;value&#39;:
        // code...
        break;
    
    default:
        // code...
        break;
}

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When there are many branches; switch is better than if else if is easy to use; for example;

if(&#39;value&#39;){
    // code...
}else if(&#39;value2&#39;){
    // code...
}else if(&#39;value3&#39;){
    // code...
}else if(&#39;value4&#39; || &#39;value5&#39;){
    // code...
}

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If you write it with switch, you can pass true; each case is equivalent to an else if;

switch (&#39;value&#39;) {
    case &#39;value1&#39;:
        // code...
        break;
    case &#39;value2&#39;:
        // code...
        break;
    case &#39;value3&#39;:
        // code...
        break;
    case &#39;value4&#39;:
    case &#39;value5&#39;:
        // code...
        break;
}

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However, it should be noted that switch is a loose comparison; that is to say, the following code can satisfy every case;

switch (123) {
    case &#39;string&#39;:
        // code...
        break;
    case &#39;string2&#39;:
        // code...
        break;
    case &#39;string3&#39;:
        // code...
        break;
}

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The way to solve this problem is to convert it to string when passing parametersstring type;

switch (strval(123)) {
    case &#39;string&#39;:
        // code...
        break;
    case &#39;string2&#39;:
        // code...
        break;
    case &#39;string3&#39;:
        // code...
        break;
}

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Things you dont know about php switch

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