PHP switch case，0 没有被识别为一个值？

Question

我在 PHP 脚本中有一个 switch case 语句，它根据 JS 文件中的 Ajax 调用提供的“日”和“小时”值返回一个字符串值。但是只要这些值为 0（即，星期日为日变量）和 0 作为小时变量的午夜）该语句不起作用并且该值返回空。我似乎找不到解决方案，这里是 PHP 函数和 Ajax 调用的代码的较短版本；

function getDayTimeData($day, $time){

    $program = "";

    switch($day){

        case 0: //Sunday

            switch($time){

                case $time < 1:

                    $program = 'Be Our Guest';

                    break;

                case $time < 6:

                    $program = 'Club Technoise';

                    break;

                case $time < 12:

                    $program = 'Morning Juice';

                    break;

                case $time < 21:

                    $program = 'Detox';

                    break;

                case $time < 24:

                    $program = 'Disco Ball';

                    break;

            }

            break;

     }

}

if(isset($_POST["DayData"]) && isset($_POST["TimeData"]))

{

    echo(getDayTimeData($_POST["DayData"],$_POST["TimeData"]));

}

这是 Jquery Ajax 脚本

function getDayTimeAjax(_day,_time){

    var def2 = $.Deferred();

    

    setTimeout(function(){

        if(xhr && xhr.readyState != 4){

            xhr.abort();

        }

        var xhr = $.ajax({

            type: 'post',

            url: 'returnPoster.php',

            contentType: "application/x-www-form-urlencoded; charset=UTF-8",

            data: {DayData: _day, TimeData: _time},

            dataType: 'text',

            success: function(x){

                programInfo = x;

                def2.resolve();

            }

        })

    },2000);

    return $.when(def2).done(function(){}).promise();

}

var d = new Date();

var programInfo = ".";

setInterval(function () { updateProgram() }, 3000);

function updateProgram(){

    getDayTimeAjax(d.getDay(),d.getHours()).done(function(){

        console.log(programInfo.trim());

    })

}

编辑：抱歉，大家看起来我在这个主题上提供了一些错误信息，因为当我设置这个线程时我有点着急。该问题仅在 $time 值为 0 时发生。这些值看起来很好，直到发生“case $time <1:”操作。从那时起，即使 $time 变量的值为 0，它也不会执行第一种情况下的代码块，因此程序变量保持为空。所有其他值都返回 switch 语句中的值。

Answer 1

这是一个小例子。这将回显基于时间的程序。为了确定日期，我建议使用 IF 而不是 switch case。$time = date("H");$day = date("w");$program = "";if($day == 0){&nbsp; switch($time){&nbsp; &nbsp; case $time < 1:&nbsp; &nbsp; &nbsp; $program = 'Be Our Guest';&nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; case $time < 6:&nbsp; &nbsp; &nbsp; $program = 'Club Technoise';&nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; case $time < 12:&nbsp; &nbsp; &nbsp; $program = 'Morning Juice';&nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; case $time < 21:&nbsp; &nbsp; &nbsp; $program = 'Detox';&nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; case $time < 24:&nbsp; &nbsp; &nbsp; $program = 'Disco Ball';&nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; }&nbsp; }else{&nbsp; &nbsp; &nbsp;.......&nbsp; }echo $program;

Answer 2

你不能像这样比较整数值和时间，switch($time){&nbsp; &nbsp; case $time < 1:&nbsp; &nbsp; &nbsp; break;}尝试比较相同类型的值。

Answer 3

你的问题出在 switch 语句上，如果你这样做：&nbsp; &nbsp; switch($time){&nbsp; &nbsp; &nbsp; &nbsp; case $time < 1:&nbsp; &nbsp; &nbsp; &nbsp; ...&nbsp; &nbsp; }并为 $time 填写一个值，例如 0：&nbsp; &nbsp; switch(0){&nbsp; &nbsp; &nbsp; &nbsp; case 0 < 1:&nbsp; &nbsp; &nbsp; &nbsp; ...&nbsp; &nbsp; }然后将调用中的值switch()与之后的值进行比较case：0 == true嗯，这个——以及所有其他比较——都是false。如果您确实想在 switch 语句中使用 less-than 进行比较，则需要执行以下操作：&nbsp; &nbsp; switch(true){&nbsp; &nbsp; &nbsp; &nbsp; case $time < 1:&nbsp; &nbsp; &nbsp; &nbsp; ...&nbsp; &nbsp; }那么比较结果就是：true == true请注意，在您的原始代码中，当 的 值$time不为 0 时，它会比较 is 3 == true，因为switch没有严格检查（它使用 ==，而不是 ===）true。无论值如何，它总是返回第一个结果“Be our guest”。

Answer 4

我认为你可以尝试这个，它也可能适用于第一个开关，但我更喜欢使用if：function getDayTimeData ($day, $time){&nbsp; &nbsp; if ((int) $day === 0) {&nbsp; &nbsp; &nbsp; &nbsp; switch($time){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; case $time < 1:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $program = 'Be Our Guest';&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; case $time < 6:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $program = 'Club Technoise';&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; case $time < 12:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $program = 'Morning Juice';&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; case $time < 21:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $program = 'Detox';&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; case $time < 24:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $program = 'Disco Ball';&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; break;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }}if(isset($_POST["DayData"]) && isset($_POST["TimeData"])){&nbsp; &nbsp; echo(getDayTimeData($_POST["DayData"],$_POST["TimeData"]));}