int = 0上的php switch语句错误 [英] php switch statement error on int = 0

问题描述

我在 php switch case 中遇到了问题.

I am having a problem in php switch case.

当我设置 $number=0 时，它应该运行第一个 case 但这里代码返回 10-20K，这是第二种情况.

When i set $number=0 it should run very first case but here this code returns 10-20K that is in second case.

我检查了比较运算符，在其他情况下测试它们返回正确的值，但这里第一种情况不会在 $number=0

I checked comparison operators, tested them in if else case they return correct values but here first case do not run on $number=0

为什么会这样?php 认为 0 为 false 或代码有问题?

Why is this happening ? php consider 0 as false or something wrong in code ?

键盘粘贴链接http://codepad.org/2glDh39K

这里也是代码

<?php

$number = 0;

    switch ($number) {
     case ($number <= 10000):
            echo "0-10K";
           break;
        case ($number > 10000 && $number <= 20000):
            echo "10-20K";
            break;
        case ($number > 20000 && $number <= 30000):
            echo "20-30K";
            break;
        case ($number > 30000 && $number <= 40000):
            echo "30-40K";
            break;
        case ($number > 40000 && $number <= 50000):
            echo "40-50K";
            break;
        case ($number > 50000 && $number <= 60000):
            echo "50-60K";
            break;
        case ($number > 60000 && $number <= 70000):
            echo "60-70K";
            break;
        case ($number > 70000 && $number <= 80000):
            echo "70-80K";
            break;
        case ($number > 80000 && $number <= 90000):
            echo "80-90K";
            break;
        case ($number > 90000):
            echo "90K+";
            break;

        default: //default
            echo "N/A";
            break;
}

?>

推荐答案

switch ($number) {
 case ($number <= 10000):   // check $number == ($number <= 10000)
       echo "0-10K";
       break;
 // you hit the below because `0 == false` is true in php
 case ($number > 10000 && $number <= 20000): // check $number == ($number > 10000 && $number <= 20000)
        echo "10-20K";
        break;
 // ...

但你可以用更少的代码做到这一点:

But you could do it with less code:

function showRange($number) {
    if ($number > 90000) {
       echo "90K+";
       return;
    }
    echo sprintf("%s-%sK", (int) ($number / 10000) * 10, ((int) ($number / 10000) +1) * 10 );
}

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