How to remove prefix in array keys

Question

I try to remove a prefix in array keys and every attempt is failing. What I want to achieve is to:

Having: Array ( [attr_Size] => 3 [attr_Colour] => 7 )

To Get: Array ( [Size] => 3 [Colour] => 7 )

Your help will be much appreciated...

Answer 1

One of the ways To Get:Array ( [Size] => 3 [Colour] => 7 ) From your Having: Array ( [attr_Size] => 3 [attr_Colour] => 7 )

$new_arr = array();
foreach($Your_arr as $key => $value) {

list($dummy, $newkey) = explode('_', $key);
$new_arr[$newkey] = $value;

}

If you think there'll be multiple underscores in keys just replace first line inside foreach with list($dummy, $newkey) = explode('attr_', $key);

Answer 2

If I understood your question, you don't have to use implode() to get what you want.

define(PREFIX, 'attr_');

$array = array('attr_Size' => 3, 'attr_Colour' => 7);

$prefixLength = strlen(PREFIX);

foreach($array as $key => $value)
{
  if (substr($key, 0, $prefixLength) === PREFIX)
  {
    $newKey = substr($key, $prefixLength);
    $array[$newKey] = $value;
    unset($array[$key]);
  }
}

print_r($array); // shows: Array ( [Size] => 3 [Colour] => 7 ) 

Answer 3

Here's something else to chew on that can be reused for multiple arrays in your application that have different key prefixes. This would be useful if you have Redis prefixed keys to remap or something of that nature.

$inputArray = array('attr_test' => 'test', 'attr_two' => 'two');

/**
 * Used to remap keys of an array by removing the prefix passed in
 *
 * Example:
 * $inputArray = array('app_test' => 'test', 'app_two' => 'two');
 * $keys = array_keys($inputArray);
 * array_walk($keys, 'removePrefix', 'app_');
 * $remappedArray = array_combine($keys, $inputArray);
 *
 * @param $value - key value to replace, should be from array_keys
 * @param $omit - unused, needed for prefix call
 * @param $prefix - prefix to string replace in keys
 */
function removePrefix(&$value, $omit, $prefix) {
    $value = str_replace($prefix, '', $value);
}

// first get all the keys to remap
$keys = array_keys($inputArray);

// perform internal iteration with prefix passed into walk function for dynamic replace of key
array_walk($keys, 'removePrefix', 'attr_');

// combine the rewritten keys and overwrite the originals
$remappedArray = array_combine($keys, $inputArray);

// see full output of comparison
var_dump($inputArray);
var_dump($remappedArray);

Output:

array(2) {
  'attr_test' =>
  string(4) "test"
  'attr_two' =>
  string(3) "two"
}
array(2) {
  'test' =>
  string(4) "test"
  'two' =>
  string(3) "two"
}