PHP how to convert a string to a boolean value

To convert string value to boolean value in PHP, you need to use the filter_var() function.

The filter_var() function can be used to validate whether a string is true or false depending on its value:

filter_var(
    mixed $value,
    int $filter = FILTER_DEFAULT,
    array|int $options = 0
): mixed

To convert a string to a boolean, you need to pass two parameters to the function:

1. The string as $value
2. FILTER_VALIDATE_BOOLEAN as the $filter argument

The FILTER_VALIDATE_BOOLEAN flag will return true for “1”, “true”, “on”, and “yes” string values. Otherwise, it returns false.

Here are some examples of converting strings to boolean values:

<?php
var_dump(filter_var("true", FILTER_VALIDATE_BOOLEAN));
var_dump(filter_var("false", FILTER_VALIDATE_BOOLEAN));
var_dump(filter_var("yes", FILTER_VALIDATE_BOOLEAN));
var_dump(filter_var("no", FILTER_VALIDATE_BOOLEAN));

The output of the code above will be:

bool(true)
bool(false)
bool(true)
bool(false)

As you can see, the filter_var() function returns boolean when you use the FILTER_VALIDATE_BOOLEAN flag.

And that’s how you convert a string to a boolean using PHP.