is_bool
(PHP 4, PHP 5)
is_bool — Finds out whether a variable is a boolean
Список параметров
- var
-
The variable being evaluated.
Возвращаемые значения
Returns TRUE if var is a boolean, FALSE otherwise.
Примеры
Пример #1 is_bool() examples
<?php
$a = false;
$b = 0;
// Since $a is a boolean, this is true
if (is_bool($a)) {
echo "Yes, this is a boolean";
}
// Since $b is not a boolean, this is not true
if (is_bool($b)) {
echo "Yes, this is a boolean";
}
?>
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- is_bool
- is_callable
- is_double
- is_float
- is_int
- is_integer
- is_long
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- is_numeric
- is_object
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- is_resource
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Коментарии
It should be stated that this function returns true if the _type_ of it's argument is boolean. It does not convert or coerce the value to a boolean type, not sure why so many comments focus on how to do this.
However, if you arrived here looking for a solution to convert a value to a boolean type, use this:
to_bool($x) { return (bool)$x; }
To check if a variable is boolean is one thing, to evaluate if the value of a variable represents a boolean condition (true or false) is another.
Here is a simple function that checks the status of the received variable in regard to boolean equivalencies (case-insensitive).
<?php
/**
* Check "Booleanic" Conditions :)
*
* @param [mixed] $variable Can be anything (string, bol, integer, etc.)
* @return [boolean] Returns TRUE for "1", "true", "on" and "yes"
* Returns FALSE for "0", "false", "off" and "no"
* Returns NULL otherwise.
*/
function is_enabled($variable)
{
if (!isset($variable)) return null;
return filter_var($variable, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
}
?>
Of course, it is a simplistic approach, but for the majority of cases it will do the job right.
And, just to put the thing from the right perspective, here's a real function that does what Phill disclosed:
<?php
/**
* Convert $variable to boolean (adapted from Phill answer)
*
* @param [mixed] $variable Can be anything
* @return [boolean] Returns the booelan equivalent to $variable based on Zend Enegine interpretation
*/
function to_bool($variable)
{
return (bool)$variable;
}
?>
I hope it helps someone. Happy coding.