PHP string "contains"

PHP 8 or newer:

Use the str_contains function.

if (str_contains($str, "."))
{
    echo 'Found it';
}

else
{
    echo 'Not found.';
}

PHP 7 or older:

if (strpos($str, '.') !== FALSE)
{
    echo 'Found it';
}

else
{
    echo 'Not found.';
}

Note that you need to use the !== operator. If you use != or <> and the '.' is found at position 0, the comparison will evaluate to true because 0 is loosely equal to false.

You can use these string functions,

strstr — Find the first occurrence of a string

stristr — Case-insensitive strstr()

strrchr — Find the last occurrence of a character in a string

strpos — Find the position of the first occurrence of a substring in a string

strpbrk — Search a string for any of a set of characters

If that doesn't help then you should use preg regular expression

preg_match — Perform a regular expression match