How Do PHP's `in_array()` and `array_search()` Functions Behave with Boolean Values and the `$strict` Parameter?

Understanding the Behavior of PHP in_array() and array_search()

PHP's in_array() and array_search() functions can exhibit unexpected behavior when dealing with arrays that contain boolean values. To resolve these inconsistencies, it's crucial to understand the inherent functionality of these functions.

Both functions have an optional third parameter, $strict, which defaults to FALSE. When $strict is set to FALSE, these functions use loose comparison (==) to evaluate values. This means they only check whether the values are equal, regardless of their type.

For example, in the array provided:

$arr = [TRUE, "some string", "something else"];

Calling in_array("test", $arr) would return TRUE even though "test" is not present in the array. This occurs because TRUE is loosely equal to "any non-empty string," including "test."

Similarly, array_search("test", $arr) would return 0, indicating that "test" is found at index 0. This is because TRUE and "any non-empty string" are considered equal by default.

To ensure accurate comparisons, it's necessary to set $strict to TRUE, which forces the functions to use strict comparison (===). Strict comparison evaluates both the value and type of the variables. Therefore, when $strict is set to TRUE:

in_array("test", $arr, true); // Returns false
array_search("test", $arr, true); // Returns -1

In conclusion, the default behavior of in_array() and array_search() can lead to unexpected results when dealing with boolean values. By setting the $strict parameter to TRUE, you can enforce strict comparison, ensuring that the functions evaluate both the value and type of variables for accurate results.

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