在PHP中重置一个foreach循环进行多次运行 [英] Reset a foreach loop in PHP for multiple runs

问题描述

我有一个需要填写9个下拉框的表单。我使用foreach循环来列出选项，但是将代码复制到第二个下拉列表中不会产生任何选项。我想这是因为结果已经循环，所以什么也找不到。

如何重置每个循环的结果？或者有一种更有效的方法可以实现这一点，有人可能知道。

这是查询：

  $ qry2 =选择ride_id，名字从tpf_rides在哪里park_id = $ park_id ORDER BY名字ASC; 
 $ res2 = $ pdo-> query（$ qry2）; 
  

这就是我正在使用的循环：

 < select name =ride_id_image> 
< option value =>选择乘车< / option> 
 
<？php foreach（$ res2 as $ row2）{
 printf（'< option value =％s>％s< / option>'PHP_EOL，$ row2 ['ride_id']，$ row2 ['name']）; 
}？> 
< / select> 
  

谢谢

解决方案 div>

有一个更有效的方法来做到这一点。

$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $' <？php

$ options =;
$ b $ foreach（$ res2 as $ row2）{
$ options。= sprintf（'< option value =％s>％s< / option>'。PHP_EOL，$ row2 ['ride_id']，$ row2 ['name']）;
}

？>


现在，无论何时打印选项，只需要输出字符串：

 < select name =ride_id_image> 
< option value =>选择乘车< / option> 
<？php echo $ options？> 
< / select> 
  

I have a form with 9 dropdown boxes that need to be populated by the same query. I use a foreach loop to list the options but copying the code to the scond dropdown produces no options. I guess it's because the result has already cycled so finds nothing.

How can I reset the result ready for each loop? Or maybe there is a more efficient way to achieve this that someone might know.

This is the query:

$qry2 = "SELECT ride_id, name FROM tpf_rides WHERE park_id = $park_id ORDER BY name ASC";
        $res2 = $pdo->query($qry2);

and this is the loop I am using:

<select name="ride_id_image">
    <option value="">Select Ride</option>

<?php   foreach ($res2 as $row2) {
    printf('<option value="%s">%s</option>' . PHP_EOL, $row2['ride_id'], $row2['name'] );
 } ?>
    </select>

Thanks

解决方案

There's a much more effective way to do this. Instead of running through the result set multiple times, write it to a string once, and then you can re-use that as often as you need to:

<?php   

$options = "";

foreach ($res2 as $row2) {
    $options .= sprintf('<option value="%s">%s</option>' . PHP_EOL, $row2['ride_id'], $row2['name'] );
 } 

 ?>

Now, whenever you want to print the options, you can just echo out your string:

<select name="ride_id_image">
    <option value="">Select Ride</option>
    <?php echo $options ?>    
    </select>

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