Detailed explanation of switch usage extension in php

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

switch (variable) {
    case 'value':
        // code...
        break;
    
    default:
        // code...
        break;
}

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

if('value'){
    // code...
}else if('value2'){
    // code...
}else if('value3'){
    // code...
}else if('value4' || 'value5'){
    // code...
}

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

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

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 'string':
        // code...
        break;
    case 'string2':
        // code...
        break;
    case 'string3':
        // code...
        break;
}

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

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

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