This is the simplest type which can be either TRUE or FALSE. Both TRUE and FALSE are case-insensitive.
To explicitly convert a value to Boolean, use the (bool) or (boolean) casts and this is also case-insensitive.
<?php $bool_true = TRUE; // Boolean true $int_test = 3; // integer 3 $bool_test = (bool)$int_test; // convert integer to Boolean ?>
When converting to Boolean, the following values are considered as FALSE.
The others are considered as TRUE. (Including string "0")