(PHP 5 >= 5.5.0, PHP 7, PHP 8)
boolval — Get the boolean value of a variable
valueThe scalar value being converted to a bool.
The bool value of value.
Example #1 boolval() examples
<?php
echo '0: '.(boolval(0) ? 'true' : 'false')."\n";
echo '42: '.(boolval(42) ? 'true' : 'false')."\n";
echo '0.0: '.(boolval(0.0) ? 'true' : 'false')."\n";
echo '4.2: '.(boolval(4.2) ? 'true' : 'false')."\n";
echo '"": '.(boolval("") ? 'true' : 'false')."\n";
echo '"string": '.(boolval("string") ? 'true' : 'false')."\n";
echo '"0": '.(boolval("0") ? 'true' : 'false')."\n";
echo '"1": '.(boolval("1") ? 'true' : 'false')."\n";
echo '[1, 2]: '.(boolval([1, 2]) ? 'true' : 'false')."\n";
echo '[]: '.(boolval([]) ? 'true' : 'false')."\n";
echo 'stdClass: '.(boolval(new stdClass) ? 'true' : 'false')."\n";
?>The above example will output:
0: false 42: true 0.0: false 4.2: true "": false "string": true "0": false "1": true [1, 2]: true []: false stdClass: true
To anyone like me who came here looking for a way to turn any value into a 0/1 that will fit into a MySQL boolean (tinyint) field:<?php$tinyint = (int) filter_var($valToCheck, FILTER_VALIDATE_BOOLEAN);?>tinyint will be 0 (zero) for values like string "false", boolean false, int 0tinyint will be 1 for values like string "true", boolean true, int 1Useful if you are accepting data that might be from a language like Javascript that sends string "false" for a boolean false.<?// Hack for old php versions to use boolval()if (!function_exists('boolval')) { function boolval($val) { return (bool) $val; }}?>function is_true($val, $return_null=false){ $boolval = ( is_string($val) ? filter_var($val, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE) : (bool) $val ); return ( $boolval===null && !$return_null ? false : $boolval );}// Return Values:is_true(new stdClass); // trueis_true([1,2]); // trueis_true([1]); // trueis_true([0]); // trueis_true(42); // trueis_true(-42); // trueis_true('true'); // trueis_true('on') // trueis_true('off') // falseis_true('yes') // trueis_true('no') // falseis_true('ja') // falseis_true('nein') // falseis_true('1'); // trueis_true(NULL); // falseis_true(0); // falseis_true('false'); // falseis_true('string'); // falseis_true('0.0'); // falseis_true('4.2'); // falseis_true('0'); // falseis_true(''); // falseis_true([]); // falseI believe that the double negation !! can perform the same task with the same result if your PHP is not up2datevar_dump(!!1, !!0, !!"test", !!"");outputs:boolean trueboolean falseboolean trueboolean falseMay the life be good to you.<?// Some way to print boolean value as string$b = true;echo ['false', 'true'][$b];?>