How to Use PHP’s is_bool() to Check Boolean Types

Syntax

bool is_bool ( mixed $var )

Parameter Description

$var

: The variable to be tested.

Return Value

If $var is a boolean, the function returns true; otherwise it returns false.

Concrete Code Example

<?php
$var1 = true;
$var2 = false;
$var3 = "true";
$var4 = 1;

// Check if variable is boolean
if (is_bool($var1)) {
    echo "变量var1是布尔类型";
} else {
    echo "变量var1不是布尔类型";
}

if (is_bool($var2)) {
    echo "变量var2是布尔类型";
} else {
    echo "变量var2不是布尔类型";
}

if (is_bool($var3)) {
    echo "变量var3是布尔类型";
} else {
    echo "变量var3不是布尔类型";
}

if (is_bool($var4)) {
    echo "变量var4是布尔类型";
} else {
    echo "变量var4不是布尔类型";
}
?>

Execution Result

变量var1是布尔类型
变量var2是布尔类型
变量var3不是布尔类型
变量var4不是布尔类型

Explanation

The example defines four variables: $var1 and $var2 are assigned the boolean values true and false, so is_bool() returns true for both, producing messages that they are boolean types. $var3 holds the string "true" and $var4 holds the integer 1; neither is a boolean, so is_bool() returns false and the script outputs that they are not boolean types.

Using is_bool() allows developers to reliably check variable types, which is useful for validating user input and ensuring data integrity and security in PHP applications.