PHP filters are used to validate and filter data from non-secure sources, such as user input.
The Filter function is an integral part of PHP core. No installation is required to use these functions.
PHP : Indicates the earliest PHP version that supports this function.
| function | describe | PHP |
|---|---|---|
| filter_has_var() | Checks whether a variable of the specified input type exists. | 5 |
| filter_id() | Returns the ID number of the specified filter. | 5 |
| filter_input() | Get input from outside the script and filter it. | 5 |
| filter_input_array() | Get multiple inputs from outside the script and filter them. | 5 |
| filter_list() | Returns an array containing all supported filters. | 5 |
| filter_var_array() | Get multiple variables and filter them. | 5 |
| filter_var() | Get a variable and filter it. | 5 |
| ID name | describe |
|---|---|
| FILTER_CALLBACK | Call user-defined functions to filter data. |
| FILTER_SANITIZE_STRING | Remove tags and remove or encode special characters. |
| FILTER_SANITIZE_STRIPPED | "string" Alias for the filter. |
| FILTER_SANITIZE_ENCODED | URL-encode string, remove or encode special characters. |
| FILTER_SANITIZE_SPECIAL_CHARS | HTML escapes the characters '"<>& and characters with an ASCII value less than 32. |
| FILTER_SANITIZE_EMAIL | Delete all characters except letters, numbers, and !#$%&'*+-/=?^_`{|}~@.[] |
| FILTER_SANITIZE_URL | Delete all characters except letters, numbers, and $-_.+!*'(),{}|^~[]`<>#%";/?:@&= |
| FILTER_SANITIZE_NUMBER_INT | Remove all characters except numbers and +- |
| FILTER_SANITIZE_NUMBER_FLOAT | Remove all characters except numbers, +- and .,eE |
| FILTER_SANITIZE_MAGIC_QUOTES | Apply addslashes(). |
| FILTER_UNSAFE_RAW | No filtering, removal or encoding of special characters is done. |
| FILTER_VALIDATE_INT | Validate the value as an integer. |
| FILTER_VALIDATE_BOOLEAN | Validate the value as a boolean option. Returns TRUE if "1", "true", "on", and "yes". Returns FALSE if "0", "false", "off", "no", and "". Otherwise return NULL. |
| FILTER_VALIDATE_FLOAT | Validate values as floating point numbers. |
| FILTER_VALIDATE_REGEXP | Validates values against regexp, a Perl-compatible regular expression. |
| FILTER_VALIDATE_URL | Validate the value as a URL. |
| FILTER_VALIDATE_EMAIL | Validate the value as an e-mail address. |
| FILTER_VALIDATE_IP | Validates the value as an IP address, IPv4 or IPv6 only or not from a private or reserved range. |