在循環裡如何使用標籤

如何在循環裡插入？

$data = array (
  0 => 
  array (
    'id' => '1',
    'name' => 'WEB编程',
    'parentid' => '0',
  ),
  1 => 
  array (
    'id' => '2',
    'name' => 'PHP',
    'parentid' => '1',
  ),
  2 => 
  array (
    'id' => '3',
    'name' => 'Ajax',
    'parentid' => '1',
  ),
  3 => 
  array (
    'id' => '4',
    'name' => 'java',
    'parentid' => '1',
  ),
  4 => 
  array (
    'id' => '5',
    'name' => 'WinForm编程',
    'parentid' => '0',
  ),
  5 => 
  array (
    'id' => '6',
    'name' => 'VB',
    'parentid' => '5',
  ),
  6 => 
  array (
    'id' => '7',
    'name' => 'VC',
    'parentid' => '5',
  ),
);

這麼一個陣列，想得到下面的效果。

<select name="categorys">
    <optgroup label="WEB编程">
        <option value="2" >PHP</option>
        <option value="3" >Ajax</option>
        <option value="4" >java</option>
    </optgroup>
 
    <optgroup label="WinForm编程">
        <option value="6" >VB</option>
        <option value="7" >VC</option>
    </optgroup>
</select>

困難在於如何在foreach裡判斷把包含在裡，折騰了半天也沒出辦法。請高手指點如何完成。

$data = array (
  0 =>  array (
    'id' => '1',
    'name' => 'WEB编程',
    'parentid' => '0',
  ),
  1 => array (
    'id' => '2',
    'name' => 'PHP',
    'parentid' => '1',
  ),
  2 => array (
    'id' => '3',
    'name' => 'Ajax',
    'parentid' => '1',
  ),
  3 => array (
    'id' => '4',
    'name' => 'java',
    'parentid' => '1',
  ),
  4 => array (
    'id' => '5',
    'name' => 'WinForm编程',
    'parentid' => '0',
  ),
  5 => array (
    'id' => '6',
    'name' => 'VB',
    'parentid' => '5',
  ),
  6 => array (
    'id' => '7',
    'name' => 'VC',
    'parentid' => '5',
  ),
);
 
echo &#39;<select name="categorys">&#39;;
foreach($data as $v) {
  if($v[&#39;parentid&#39;] == 0)
    echo "<optgroup label=&#39;$v[name]&#39;>";
  else
    echo "<option value=&#39;$v[id]&#39; >$v[name]</option>";
}
echo &#39;</select>&#39;;

嘮叨大哥，你上面的操作還是缺了結束符啊

我就是在苦悶如何把這個加進去。

echo "<optgroup label=&#39;$v[name]&#39;>$v[name]</optgroup>";

稍微改下來就行了。

$data = array (
  0 => 
  array (
    'id' => '1',
    'name' => 'WEB编程',
    'parentid' => '0',
  ),
  1 => 
  array (
    'id' => '2',
    'name' => 'PHP',
    'parentid' => '1',
  ),
  2 => 
  array (
    'id' => '3',
    'name' => 'Ajax',
    'parentid' => '1',
  ),
  3 => 
  array (
    'id' => '4',
    'name' => 'java',
    'parentid' => '1',
  ),
  4 => 
  array (
    'id' => '5',
    'name' => 'WinForm编程',
    'parentid' => '0',
  ),
  5 => 
  array (
    'id' => '6',
    'name' => 'VB',
    'parentid' => '5',
  ),
  6 => 
  array (
    'id' => '7',
    'name' => 'VC',
    'parentid' => '5',
  ),
);
$tempArray = array();
foreach($data as $item){
    $tempArray[$item['parentid']][$item['id']] = $item['name'];
}
echo '';
foreach($tempArray[0] as $parentid=>$name){
    echo "";
    foreach($tempArray[$parentid] as $id=>$name){
        echo "$name";
    }
    echo '';
}
echo '';

只是foreach了三次怕效率較差，不知還沒有有別的方法。

重做陣列的話…

$data = array (
  array (
    'id' => '1',
    'name' => 'WEB编程',
    'parentid' => '0',
    'sub'=>
     array(
          array(
            'id' => '2',
            'name' => 'PHP',
            'parentid' => '1',
          ),
          array (
            'id' => '3',
            'name' => 'Ajax',
            'parentid' => '1',
          ),
          array (
            'id' => '4',
            'name' => 'java',
            'parentid' => '1',
          )
    )
  ),
  array (
    'id' => '5',
    'name' => 'WinForm编程',
    'parentid' => '0',
    'sub'=>
    array(
          array (
            'id' => '6',
            'name' => 'VB',
            'parentid' => '5',
          ),
          array (
            'id' => '7',
            'name' => 'VC',
            'parentid' => '5',
          )
    )
  )
);
echo &#39;<select style="width:200px;">&#39;;
for($i=0,$il=count($data);$i<$il;$i++){
    echo &#39;<optgroup label="&#39;.$data[$i][&#39;name&#39;].&#39;">&#39;;
    for($j=0,$jl=count($data[$i][&#39;sub&#39;]);$j<$jl;$j++){
        echo &#39;<option>&#39;.$data[$i][&#39;sub&#39;][$j][&#39;name&#39;].&#39;</option>&#39;;
    }
    echo &#39;<optgroup>&#39;;
}
echo &#39;</select>&#39;;

   是嗎？
哦，是少了個 
不過我測試程式碼時並沒有感覺出有與沒有的差異

一定要有的話，就加個開關變數。要多次循環幹什麼？

echo &#39;<select name="categorys">&#39;;
$k = false;
foreach($data as $v) {
  if($v[&#39;parentid&#39;] == 0) {
    echo "<optgroup label=&#39;$v[name]&#39;>";
    $k = true;
  }else {
    if($k) echo &#39;</optgroup>&#39;;
    echo "<option value=&#39;$v[id]&#39; >$v[name]</option>";
    $k = false;
  }
}
echo &#39;</select>&#39;;

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