array_key_exists() returns TRUE
if the given key
is set in the array. key
can be any value possible for an array index.
Value to check.
An array with keys to check.
Returns TRUE
on success or FALSE
on failure.
For backward compatibility reasons, array_key_exists() will also return TRUE
if key
is a property defined within an object given as array
. This behaviour should not be relied upon, and care should be taken to ensure that array
is an array.
To check whether a property exists in an object, use property_exists().
<?php $search_array = array('first' => 1, 'second' => 4); if (array_key_exists('first', $search_array)) { echo "The 'first' element is in the array"; } ?>
isset() does not return TRUE
for array keys that correspond to a NULL
value, while array_key_exists() does.
<?php $search_array = array('first' => null, 'second' => 4); // returns false isset($search_array['first']); // returns true array_key_exists('first', $search_array); ?>
isset() -
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