How to convert string to boolean php

How can I convert string to boolean?

$string = 'false';

$test_mode_mail = settype($string, 'boolean');

var_dump($test_mode_mail);

if($test_mode_mail) echo 'test mode is on.';

it returns,

boolean true

but it should be boolean false.

Answer

Strings always evaluate to boolean true unless they have a value that's considered "empty" by PHP (taken from the documentation for empty):

1. "" (an empty string);


2. "0" (0 as a string)

If you need to set a boolean based on the text value of a string, then you'll need to check for the presence or otherwise of that value.

$test_mode_mail = $string === 'true'? true: false;

EDIT: The above code is intended for clarity of understanding. In actual use the following code may be more appropriate:

$test_mode_mail = ($string === 'true');