PHP | Filter Functions
Since PHP 5.2.0, the filter functions are enabled by default. You can use them directly in your code without any further installation.
filter_has_var()
Checks if the variable of the specified type exists
filter_id()
Returns the ID number of a specified filter
filter_input()
Gets a specific external variable by name and optionally filters it
filter_input_array()
Gets multiple external variables and optionally filters them
filter_list()
Returns an array of all supported filters
filter_var_array()
Gets multiple variables and optionally filters them
filter_var()
Filters a variable with a specified filter
PHP Sanitize Filters
The sanitize filters are used to sanitize or clean the user inputs.
FILTER_SANITIZE_EMAIL
Remove all characters except letters, digits, and !#$%&’*+-/=?^_`{|}~@.[]
FILTER_SANITIZE_ENCODED
URL-encode string, optionally strips or encode special characters.
FILTER_SANITIZE_MAGIC_QUOTES
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Apply addslashes().
FILTER_SANITIZE_NUMBER_FLOAT
Remove all characters except digits, +- and optionally .,eE
FILTER_SANITIZE_NUMBER_INT
Remove all characters except the digits, plus (+), and minus (-) sign.
FILTER_SANITIZE_SPECIAL_CHARS
HTML-escape ‘“<>& and characters with ASCII value less than 32, optionally strip or encode other special characters.
FILTER_SANITIZE_STRING
Strip tags, optionally strip or encode special characters.
FILTER_SANITIZE_STRIPPED
Alias of “string” filter.
FILTER_SANITIZE_URL
Remove all characters except letters, digits, and $-_.+!*’(),{}|\\^~[]`<>#%”;/?:@&=
FILTER_UNSAFE_RAW
Do nothing, optionally strip or encode special characters.
Validate Filters
The sanitize filters are used to validate the user inputs.
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.
