Development

PHP is_bool() Function

In this tutorial, we will cover one of the fundamental methods in PHP to determine whether a given variable is a Boolean value or not.
Captain Salem 2 min read
PHP is_bool() Function

Variable evaluation refers to the method of determining whether a given PHP variable is a specific type or within a given string or expression.

Variable evaluation is a fantastic feature is it can allow you to quickly process and evaluate whether a given user input is a specific type or not. This can help you sanitize user data and prevent malicious content from passing through.

PHP is_bool() Function

As the name suggests, the is_bool() method allows to determine whether a given input is a Boolean Value or not.

The function syntax is as shown below:

is_bool(mixed $value): bool

The function accepts only one parameter:

  1. value - this refers to the value whose type you wish to evaluate.

The function returns a Boolean True is the input is bool type and False if otherwise.

Examples

The following example demonstrates how to use the is_bool() method to check if a given variable is a Boolean Type.

$my_var = true;
if (is_bool($my_var)) {
  echo "The variable is a boolean value.";
} else {
  echo "The variable is not a boolean value.";
}

Output:

The variable is a boolean value.

Example 2

We can also use the is_bool() method to check if the return value of a given function is a boolean as demonstrated in the snippet below:

function is_active($user) {
  // some code to check if the user is active
  return true;
}

if (is_bool(is_active("Peter"))) {
  echo "The function returned a boolean value.";
} else {
  echo "The function did not return a boolean value.";
}

Output:

The function returned a boolean value.

Example 3

We can also use the is_bool() method to validate user input as demonstrated in the code below:

$user_input = "true";

if (is_bool($user_input)) {
  echo "The input is a boolean value.";
} else {
  echo "The input is not a boolean value.";
}

Resulting output:

The input is not a boolean value.

In this case, the is_bool() function returns false asthe value of $user_input is a string, not a boolean value.

Conclusion

In this post, we discussed how to work with the is_bool() function to perform a variety of tasks. For example, we discussed to validate a function return value. We also used it to validate the user input.

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