Question

mixed array_search  ( mixed $needle  , array $haystack  [, bool $strict  ] )

If the third parameter strict  is set to TRUE  then the array_search() function will also check the types of the needle  in the haystack . 

I don’t see what it means,maybe an example can help?

Answer 1

If the last argument is true, it will use strict (also known as identity) comparison (===) when searching the array.

The equality comparison (==) compares the value where as the identity comparison (===) compares the value and the type.

'0' == 0 ; //true, the string is converted to an integer and then the are compared.
'0' === 0; //false, a string is not equal to a integer

You will find more information in this question How do the equality (== double equals) and identity (=== triple equals) comparison operators differ?

This means that if you had an array of numbers

$a = array(0,1,2,3,4);

Using a strict comparison for the string value '2' will return false (not find a match) as there are no strings with the value '2'.

array_search('2', $a, true); //returns false

However if you don’t do a strict search, the string is implicitly converted into an integer (or the other way around) and it returns the index of 2, as 2 == '2'

array_search('2', $a, false); //returns 2