


PHP two-dimensional array is an array composed of multiple one-dimensional arrays, where each one-dimensional array contains multiple elements. When processing such an array, sometimes we need to modify the keys in the two-dimensional array to meet our business needs. This article will introduce how to modify the keys in a two-dimensional array in PHP.
1. Modify the specified keys of all sub-arrays
Sometimes, we need to modify the specified keys of all sub-arrays in a two-dimensional array to a new key name. You can use the array_map function to do this accomplish. The array_map function can apply a custom function to each element of the array.
The following is a code example:
function changeKey($arr, $oldkey, $newkey){ if(!is_array($arr)){ return $arr; } $result = array(); foreach($arr as $key=>$val){ if(is_array($val)){ $result[$key] = changeKey($val, $oldkey, $newkey); } else { $result[$key] = $val; if($key == $oldkey){ $result[$newkey] = $val; unset($result[$oldkey]); } } } return $result; } $oldArray = array( array('id'=>1, 'name'=>'php', 'type'=>'backend'), array('id'=>2, 'name'=>'js', 'type'=>'frontend') ); $newArray = array_map(function($arr){ return changeKey($arr, 'type', 'category'); }, $oldArray); print_r($newArray);
The above code changes the 'type' key in all sub-arrays in $oldArray to the 'category' key. The output result is as follows:
Array ( [0] => Array ( [id] => 1 [name] => php [category] => backend ) [1] => Array ( [id] => 2 [name] => js [category] => frontend ) )
2. Modify the specified key of the specified sub-array
Sometimes, we only need to modify the specified key of a certain sub-array in the two-dimensional array. You can directly modify the sub-array. Array to achieve. The following is a code example:
$oldArray = array( array('id'=>1, 'name'=>'php', 'type'=>'backend'), array('id'=>2, 'name'=>'js', 'type'=>'frontend') ); foreach($oldArray as &$arr){ if($arr['id'] == 1){ $arr['type'] = 'server side'; } } print_r($oldArray);
The above code changes the 'type' key of the subarray with $id 1 in $oldArray to 'server side'. The output results are as follows:
Array ( [0] => Array ( [id] => 1 [name] => php [type] => server side ) [1] => Array ( [id] => 2 [name] => js [type] => frontend ) )
3. Conclusion
PHP two-dimensional array is one of the data structures widely used in PHP. Once you master the method of modifying the keys in the PHP two-dimensional array, you can easily do it data processing. This article introduces two methods of modifying keys in PHP two-dimensional arrays through examples. I hope it will be helpful to everyone.
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