is_bool
(PHP 4, PHP 5, PHP 7, PHP 8)
is_bool — 检测变量是否是布尔值
参数
-
value -
要检查的变量。
返回值
如果 value 是布尔值则返回 true，否则返回 false。
范例
示例 #1 is_bool() 示例
<?php
$a = false;
$b = 0;
// 因为 $a 是布尔值，所以结果为 true
if (is_bool($a) === true) {
echo "Yes, this is a boolean";
}
// 因为 $b 不是布尔值，所以结果为 false
if (is_bool($b) === false) {
echo "No, this is not a boolean";
}
?>
参见
- is_float() - 检测变量是否是浮点型
- is_int() - 检测变量是否是整数
- is_string() - 检测变量是否是字符串
- is_object() - 检测变量是否是一个对象
- is_array() - 检测变量是否是数组
add a note
User Contributed Notes 3 notes
Julio Marchi ¶
2 years ago
The function Michael Smith published doesn't do the work as it should.
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 a simple function that checks the status of the received variable in regards 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 thing in 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)$variable;
}
?>
I hope it helps someone. Happy coding.
phil ¶
3 years ago
It should be stated that this function returns true if the _type_ of it's argument is boolean. It does not convert or coerce the value to a boolean type, not sure why so many comments focus on how to do this.
However, if you arrived here looking for a solution to convert a value to a boolean type, use this:
to_bool($x) { return (bool)$x; }
Michael Smith ¶
8 years ago
The function in the last comment also converts the string 'false' to a true boolean. Here's a function that does what I think was intended:
<?php
function toBool($var) {
if (!is_string($var)) return (bool) $var;
switch (strtolower($var)) {
case '1':
case 'true':
case 'on':
case 'yes':
case 'y':
return true;
default:
return false;
}
}