Php – How to convert string to boolean php

booleancastingPHPstring

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.

Best Answer

This method was posted by @lauthiamkok in the comments. I'm posting it here as an answer to call more attention to it.

Depending on your needs, you should consider using filter_var() with the FILTER_VALIDATE_BOOLEAN flag.

filter_var(    true, FILTER_VALIDATE_BOOLEAN); // true
filter_var(    'true', FILTER_VALIDATE_BOOLEAN); // true
filter_var(         1, FILTER_VALIDATE_BOOLEAN); // true
filter_var(       '1', FILTER_VALIDATE_BOOLEAN); // true
filter_var(      'on', FILTER_VALIDATE_BOOLEAN); // true
filter_var(     'yes', FILTER_VALIDATE_BOOLEAN); // true

filter_var(   false, FILTER_VALIDATE_BOOLEAN); // false
filter_var(   'false', FILTER_VALIDATE_BOOLEAN); // false
filter_var(         0, FILTER_VALIDATE_BOOLEAN); // false
filter_var(       '0', FILTER_VALIDATE_BOOLEAN); // false
filter_var(     'off', FILTER_VALIDATE_BOOLEAN); // false
filter_var(      'no', FILTER_VALIDATE_BOOLEAN); // false
filter_var('asdfasdf', FILTER_VALIDATE_BOOLEAN); // false
filter_var(        '', FILTER_VALIDATE_BOOLEAN); // false
filter_var(      null, FILTER_VALIDATE_BOOLEAN); // false

This is the style that Microsoft tends to use in their examples.

It appears that the guidance in this area may have changed, as StyleCop now enforces the use of the C# specific aliases.

Bash – How to check if a string contains a substring in Bash

You can use Marcus's answer (* wildcards) outside a case statement, too, if you use double brackets:

string='My long string'
if [[ $string == *"My long"* ]]; then
  echo "It's there!"
fi

Note that spaces in the needle string need to be placed between double quotes, and the * wildcards should be outside. Also note that a simple comparison operator is used (i.e. ==), not the regex operator =~.

Best Answer

Related Solutions

C# – the difference between String and string in C#

This is the style that Microsoft tends to use in their examples.

Bash – How to check if a string contains a substring in Bash

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