PHP Developer Question:

FILTER_VALIDATE_BOOLEAN
Returns TRUE for "1", "true", "on" and "yes". Returns FALSE otherwise.

FILTER_VALIDATE_EMAIL
Validates value as e-mail.

FILTER_VALIDATE_FLOAT
Validates value as float.

FILTER_VALIDATE_INT
Validates value as integer optionally from the specified range.

FILTER_VALIDATE_IP
Validates value as IP address, optionally only IPv4 or IPv6 or not from private or reserved ranges.

FILTER_VALIDATE_REGEXP
Validates value against regexp, a Perl-compatible regular expression.

FILTER_VALIDATE_URL
Validates value as URL, optionally with required components.