Checking String for Specific Word

The task of checking whether a string contains a particular word is a common operation in programming. Consider the following code:

$a = 'How are you?';

if ($a contains 'are')
    echo 'true';

What is the correct way to write the statement if ($a contains 'are')?

Solution: str_contains Function (PHP 8)

From PHP 8 onwards, str_contains provides a straightforward solution:

if (str_contains('How are you', 'are')) {
    echo 'true';
}

However, it's important to note that str_contains always returns true if the substring to search for ($needle) is empty. To avoid this, verify that $needle is non-empty before using str_contains.

Alternatives (Pre-PHP 8)

Before PHP 8, the strpos() function was used for this purpose:

$haystack = 'How are you?';
$needle = 'are';

if (strpos($haystack, $needle) !== false) {
    echo 'true';
}

In this case, strpos() returns the position of the $needle within the $haystack, or false if not found. However, using !== false is necessary since 0 is a valid position and also evaluates to falsey.