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is_bool

(PHP 4, PHP 5, PHP 7)

is_bool Finds out whether a variable is a boolean

Description

is_bool ( mixed $var ) : bool

Finds whether the given variable is a boolean.

Parameters

var

The variable being evaluated.

Return Values

Returns TRUE if var is a boolean, FALSE otherwise.

Examples

Example #1 is_bool() examples

<?php
$a 
false;
$b 0;

// Since $a is a boolean, it will return true
if (is_bool($a) === true) {
    echo 
"Yes, this is a boolean";
}

// Since $b is not a boolean, it will return false
if (is_bool($b) === false) {
    echo 
"No, this is not a boolean";
}
?>

See Also

  • is_float() - Finds whether the type of a variable is float
  • is_int() - Find whether the type of a variable is integer
  • is_string() - Find whether the type of a variable is string
  • is_object() - Finds whether a variable is an object
  • is_array() - Finds whether a variable is an array

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User Contributed Notes 2 notes

up
7
phil
7 months 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; }
up
-2
Michael Smith
5 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;
  }
}
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