if语句在for循环中的while循环内部不起作用

时间:2013-04-17 21:31:57

标签: php if-statement for-loop while-loop

我已经花了好几个小时来解决这个问题,并在网上搜索答案,但没有找到任何帮助我的方法。

所以,我正在为酒店网站制作过滤器,酒店搜索的标准之一是酒店所在的区域。我使用GET方法:

<?php if (isset($_GET['District1'])){
    $district1= ($_GET["District1"]);
    }else ($district1=0);
if (isset($_GET['District2'])){
    $district2= ($_GET["District2"]);
    }else ($district2=0);
if (isset($_GET['District3'])){
    $district3= ($_GET["District3"]);
    }else ($district3=0);
if (isset($_GET['District4'])){
    $district4= ($_GET["District4"]);
    }else ($district4=0);
?>

其中$ district1,$ district2,$ district3,$ district4是该市的4个不同地区。

我要做的是使用 for loop 来构建区变量(变量名末尾的数字将按1递增:$ district1 .. 2 < / strong> .. 3 .. 4 ),

然后将这些分区变量放在 if子句中,该子句位于 while循环内,如下所示:

<?php 
$districts_filter_query="SELECT * FROM districts_table ";
        $districts_filter_result = mysql_query($districts_filter_query, $connect);
        $districts_filter_row = mysql_fetch_array($districts_filter_result);
        for($count = 1; $count <= 4 ; $count++){

do {

        $district_name = $districts_filter_row['district_name'];
        $district_value = $districts_filter_row['district_value'];



    echo '
           <label for="group13"> <p ';  ?> <?php 
            if ( eval(' return $district'.$count.';') !=0){echo 'class="greenBG"';}
                    else {echo ' class="checkbox" ';}?> <?php echo ' >
                    <input type="checkbox" name="District'.$count.'" id="group13" value="'.$district_value.'"
                         onClick="this.form.submit();" ';?> 
                    <?php if ( eval (' return $district'.$count.';') !=0){echo ' checked ';};?><?php echo '/> '.$district_name.' 
                </p>
           </label> ';

    }
    while($districts_filter_row = mysql_fetch_array ($districts_filter_result));
    }
?>

问题出在这里,我猜:eval('return $ district'。$ count。';'),由此我尝试构建区变量名。但它不起作用。

如果我使用此代码,一切都很完美:

            <label for="group1"> <p <?php 
            if ($district1!=0){echo 'class="greenBG"';}
                    else echo 'class="checkbox"';?>>
                    <input type="checkbox" name="District1" id="group1" value='1013' onClick="this.form.submit();" 
                    <?php if ($district1!=0){echo 'checked ';};?>/> district1
                </p>
           </label>
            <label for="group2"> <p <?php 
             if ($district2!=0){echo   'class="greenBG"';}
                    else echo 'class="checkbox"';?>>
                    <input type="checkbox" name="District2" id="group2" value='1014' onClick="this.form.submit();" 
                    <?php if ($district2!=0){echo 'checked ';};?>/> district2
                </p>
           </label>
            <label for="group3"> <p <?php 
            if ($district3!=0){echo 'class="greenBG"';}
                    else echo 'class="checkbox"';?>>
                    <input type="checkbox" name="District3" id="group3" value='1015' onClick="this.form.submit();" 
                    <?php if ($district3!=0){echo 'checked ';};?>/> district3
                </p>
           </label>
             <label for="group4"> <p <?php 
            if ($district4!=0){echo 'class="greenBG"';}
                    else echo 'class="checkbox"';?>>
                    <input type="checkbox" name="District4" id="group4" value='1016' onClick="this.form.submit();" 
                    <?php if ($district4!=0){echo 'checked ';};?>/>  district4
                </p>
           </label>

但这不适合我,因为有超过30个区,并且需要花费大量的时间和精力才能对代码进行微小的更改。

如果你帮我解决这个问题并节省我的时间,我会很高兴。谢谢,希望我的问题很清楚。

2 个答案:

答案 0 :(得分:0)

作为一种方法有点令人费解,但摆脱eval的快速解决方案是使用变量变量:

<?php
$district_name = "district$count";
if ($$district_name != 0) { ... }
?>

......虽然更好的解决方案是使用数组并循环遍历它。

答案 1 :(得分:0)

使用http://php.net/manual/en/language.variables.variable.php代替一些丑陋的eval()。 (例如${"district$count"}

$count = 0;
do {
    $count++;
    $district_name = $districts_filter_row['district_name'];
    $district_value = $districts_filter_row['district_value'];
?>
<label for="group<?php echo $count; ?>">
    <p <?php 
        if (${"district$count"} != 0) echo 'class="greenBG"';
        else echo 'class="checkbox"'; ?>>
        <input type="checkbox" name="District<?php echo $count; ?>" id="group<?php echo $count; ?>" value='<?php echo $district_value; ?>' onClick="this.form.submit();" 
        <?php if (${"district$count"} != 0) echo 'checked '; ?>/> <?php echo $district_name; ?>
    </p>
</label>
<?php
}
while($districts_filter_row = mysql_fetch_array ($districts_filter_result));

然后删除它以循环它。