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I have some strange issue with isset() function in PHP. Let me show... .
<?php
$aTestArray = array(
'index' => array(
'index' => 'Główna'
),
'dodaj' => 'Dodaj ogłoszenie',
);
var_dump( isset($aTestArray['index']) );
var_dump( isset($aTestArray['index']['index']) );
var_dump( isset($aTestArray['dodaj']) );
var_dump( isset($aTestArray['index']['none']) );
var_dump( isset($aTestArray['index']['none']['none2']) );
// This unexpectedly returns TRUE
var_dump( isset($aTestArray['dodaj']['none']) );
var_dump( isset($aTestArray['dodaj']['none']['none2']) );
?>
The var_dump's will return:
bool(true)
bool(true)
bool(true)
bool(false)
bool(false)
bool(true)
bool(false)
Why the sixth var_dump() return TRUE ?
862
Difference between isset() and array_key_exists() Function: The main difference between isset() and array_key_exists() function is that the array_key_exists() function will definitely tells if a key exists in an array, whereas isset() will only return true if the key/variable exists and is not null.
The isset() function is an inbuilt function in PHP which checks whether a variable is set and is not NULL. This function also checks if a declared variable, array or array key has null value, if it does, isset() returns false, it returns true in all other possible cases.
The equivalent of isset($var) for a function return value is func() === null . isset basically does a !== null comparison, without throwing an error if the tested variable does not exist.
isset: Returns true for empty string, False, 0 or an undefined variable.
When using the [] operators on a string, it will expect an integer value. If it does not get one, it will convert it. ['none'] is converted to [0] which, in your case, is a D.
114
It is because PHP is written in C. So since $aTestArray['dodaj'] is the string:
$aTestArray['dodaj']['none']
is the same as
$aTestArray['dodaj'][0]
because
var_dump( (int) 'none')
is 0
38
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