Heim >Backend-Entwicklung >PHP-Tutorial >这两种php数组的写法有何不同?
一:
<code>while(!$param->end) { $param_array[$param->field['param_group_id']]['param_group_name'] = $param->field['param_group_name']; $param_array[$param->field['param_group_id']]['values'][$param->field['param_id']] = $param->field['param_name']; $param->move_next(); } </code>
二:
<code>while(!$param->end) { $param_array[$param->field['param_group_id']] = array( 'param_group_name' => $param->field['param_group_name'], 'values' => array( $param->field['param_id'] => $param->field['param_name'] ) ); $param->move_next(); } </code>
while循环每次取$param->field中的一行数据,在第二中写法中$param_array['some_id']['values']数组中最终只有一个元素,不知道怎么回事?
一:
<code>while(!$param->end) { $param_array[$param->field['param_group_id']]['param_group_name'] = $param->field['param_group_name']; $param_array[$param->field['param_group_id']]['values'][$param->field['param_id']] = $param->field['param_name']; $param->move_next(); } </code>
二:
<code>while(!$param->end) { $param_array[$param->field['param_group_id']] = array( 'param_group_name' => $param->field['param_group_name'], 'values' => array( $param->field['param_id'] => $param->field['param_name'] ) ); $param->move_next(); } </code>
while循环每次取$param->field中的一行数据,在第二中写法中$param_array['some_id']['values']数组中最终只有一个元素,不知道怎么回事?
第二种写法每次都是重新定义 $param_aray[ $param->field['param_group_id'] ]
这个元素,当 $param->field['param_group_id']
重复的时候会造成对 $param_aray[ $param->field['param_group_id'] ]
的覆盖,看 DEMO 更清楚一点:
<code>$data = array( array("id"=> 1, "name"=>"a", "group"=>2, "value"=>10), array("id"=> 2, "name"=>"b", "group"=>1, "value"=>11), array("id"=> 3, "name"=>"c", "group"=>2, "value"=>12), array("id"=> 4, "name"=>"d", "group"=>1, "value"=>13), array("id"=> 5, "name"=>"e", "group"=>2, "value"=>14), ); /* 第一种 */ $result = array(); foreach( $data as $item ) { $result[ $item['group'] ]['value'][ $item['id'] ] = $item['value'] } var_dump( $result ); /* 第二种 */ $result = array(); foreach( $data as $item ) { $result[ $item['group'] ] = array( "value" => array( $item['id'] => $item['value'] ) ); } var_dump( $result ); </code>