Answers for "if collection key exists php"

php key in array exists

<?php
$search_array = array('first' => null, 'second' => 4);

// returns false
isset($search_array['first']);

// returns true
array_key_exists('first', $search_array);
?>

php key_exists

PHP function key_exists($key, array $array) bool
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Checks if the given key or index exists in the array. The name of this function is array_key_exists() in PHP > 4.0.6.

Parameters:
int|string--$key--Value to check.
array--$array--An array with keys to check.
  
Returns:true on success or false on failure.