Introduction to PHP Filter

PHP filters are used to validate and filter data from non-secure sources (such as user input).

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Installation

The Filter function is an integral part of the PHP core. No installation is required to use these functions.

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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 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

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PHP Filters

##FILTER_SANITIZE_NUMBER_FLOATRemove all Characters, except numbers, +- and .,eEFILTER_SANITIZE_MAGIC_QUOTESApply addslashes(). FILTER_UNSAFE_RAW Does not do any filtering, remove or encode special characters. FILTER_VALIDATE_INTValidate the value as an integer. FILTER_VALIDATE_BOOLEANValidate the value as a Boolean option. Returns TRUE if "1", "true", "on", and "yes". Returns FALSE if "0", "false", "off", "no", and "". Otherwise NULL is returned. FILTER_VALIDATE_FLOATValidate the value as a floating point number. FILTER_VALIDATE_REGEXPValidate values ​​against regexp, a Perl-compatible regular expression. FILTER_VALIDATE_URLValidate the value as a URL. FILTER_VALIDATE_EMAILValidate the value as an e-mail address. FILTER_VALIDATE_IPValidate the value as an IP address, only IPv4 or IPv6 or not from a private or reserved range.

ID Name	Description
FILTER_CALLBACK	Call user-defined functions to filter data.
FILTER_SANITIZE_STRING	Remove tags, 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 escape character '"<>& and characters with ASCII value less than 32.
FILTER_SANITIZE_EMAIL	Remove all characters except letters, numbers and !#$%&'*+-/=?^_`{|}~@.[]
FILTER_SANITIZE_URL	Remove all characters except letters, numbers and $-_.+!*'(),{}|\^~[]`<>#%";/?:@& =
FILTER_SANITIZE_NUMBER_INT	Remove all characters except numbers and +-