PHP filter_var() function Filter function_PHP tutorial

The filter_var() function filters variables through a specified filter.
Returns filtered data if successful, false if failed.
Syntax
filter_var(variable, filter, options)variable: required. Specifies the variables to filter.
filter: optional. Specifies the ID of the filter to use. (See list of FiltersIDs below)
options: Specifies an array containing flags/options. Check the possible flags and options for each filter.

Copy code The code is as follows:

@header('content-type:text/html; charset=utf-8;');
$email_a='jcifox@gmail.com';
$email_b='@jcifox@gmail.com';
$email_c='jcifoxgmail.com';
$ip_a='0.0.0.0';
$ip_b='255.255.255.255';
$ip_c='0.0.0.265';
echo $email_a.'　:';
echo (filter_var($email_a,FILTER_VALIDATE_EMAIL))?'is valid':'is not valid';
echo '

';
echo $email_b.'　: ';
echo (filter_var($email_b,FILTER_VALIDATE_EMAIL))?'is valid':'is not valid';
echo '

';
echo $email_c.'　:';
echo (filter_var($email_c,FILTER_VALIDATE_EMAIL))?'is valid':'is not valid';
echo '

' ;
echo $ip_a.'　:';
echo (filter_var($ip_a,FILTER_VALIDATE_IP))?'is valid':'is not valid';
echo '
< br />';
echo $ip_b.'　:';
echo (filter_var($ip_b,FILTER_VALIDATE_IP))?'is valid':'is not valid';
echo '

';
echo $ip_c.'　:';
echo (filter_var($ip_c,FILTER_VALIDATE_IP))?'is valid':'is not valid';
?>

FiltersID Name: Description
FILTER_CALLBACK: Call user-defined function to filter data.
FILTER_SANITIZE_STRING: Remove tags, remove or encode special characters.
FILTER_SANITIZE_STRIPPED: Alias ​​for "string" filter.
FILTER_SANITIZE_ENCODED: URL-encode string, remove or encode special characters.
FILTER_SANITIZE_SPECIAL_CHARS: HTML escape characters '"<>& and characters with ASCII value less than 32.
FILTER_SANITIZE_EMAIL: Remove 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.
FILTER_VALIDATE_INT: Validates values ​​as integers in the specified range.
FILTER_VALIDATE_BOOLEAN: Returns true if it is "1", "true", "on" and "yes", and returns if it is "0", "false", "off", "no" and "" false. Otherwise NULL is returned.
FILTER_VALIDATE_FLOAT: Validate value as floating point number.
FILTER_VALIDATE_REGEXP: Validate values ​​based on regexp, a Perl-compatible regular expression.
FILTER_VALIDATE_URL: Validate the value as a URL.
FILTER_VALIDATE_EMAIL: Validate value as e-mail.
FILTER_VALIDATE_IP: Validate the value as an IP address.

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