PHP filter_var () function

Introduction to filter in php Tutorial

Php filters are used to verify and filter data from unsafe sources (such as user input.

Install

The filter function is a core component of php. These functions can be used without installation.

Php filter function

Php: indicates the earliest php version that supports this function.

Function	Description	Php
Filter_has_var ()	Check whether a variable of the specified input type exists.	5
Filter_id ()	Returns the id of the specified filter.	5
Filter_input ()	Obtain and filter the input from outside the script.	5
Filter_input_array ()	Obtain multiple inputs from outside the script and filter them out.	5
Filter_list ()	Returns an array containing all the supported filters.	5
Filter_var_array ()	Obtain and filter multiple variables.	5
Filter_var ()	Obtain and filter a variable.	5

Php filters

Id	Description
Filter_callback	You can call a user-defined function to filter data.
Filter_sanitize_string	Remove tags, remove or encode special characters.
Filter_sanitize_stripped	The alias of the "string" filter.
Filter_sanitize_encoded	Url-encode string to remove or encode special characters.
Filter_sanitize_special_chars	Html escape character '"<> & characters with ascii values smaller 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	Delete all characters except numbers and +-
Filter_sanitize_number_float	Delete all characters except numbers, +-, and., ee.
Filter_sanitize_magic_quotes	Apply addslashes ().
Filter_unsafe_raw	Do not filter, remove, or encode special characters.
Filter_validate_int	The value is verified by an integer in the specified range.
Filter_validate_boolean	If it is "1", "true", "on", and "yes", true is returned. If it is "0", "false", "off ", "no" and "", false is returned. Otherwise, null is returned.
Filter_validate_float	Verify the value with a floating point number.
Filter_validate_regexp	Verify the value based on regexp and perl-compatible regular expressions.
Filter_validate_url	Use the value as the url for verification.
Filter_validate_email	Use the value as email for verification.
Filter_validate_ip	Use the value as the ip address for verification.