(PHP 4, PHP 5, PHP 7)
is_bool — 检测变量是否是布尔型
如果 var
是 boolean 则返回 TRUE。
Example #1 is_bool() 示例
<?php
$a = false;
$b = 0;
// 因为 $a 是布尔型，所以结果为真
if (is_bool($a)) {
print "Yes, this is a boolean";
}
// 因为 $b 不是布尔型，所以结果为非真
if (is_bool($b)) {
print "Yes, this is a boolean";
}
?>
参见 is_array()、is_float()、is_int()、is_integer()、is_string() 和 is_object()。
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; }
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;
}
}