How to use filter_var() function in PHP? (code example)

In PHP, the filter_var() function will use the specified filter to filter variables; it can filter the data passed by the user. The following article will introduce to you the usage of filter_var() function. I hope it will be helpful to you. [Video tutorial recommendation:PHP tutorial]

##PHP filter_var() function

The filter_var() function filters a variable using the specified filter; it can be used to validate and filter data.

Basic syntax

filter_var(var, filtername, options)

Parameters:filter_var() function accepts three parameters

●var: indicates what to filter Variable, cannot be omitted (required parameter).

● filtername: used to specify the ID or name of the filter to be used. The default value is FILTER_DEFAULT, which causes no filtering; can be omitted.

● Options: Used to specify one or more flags/options to be used. Checks each filter for possible options and flags; may be omitted.

Return value:If the filtering is successful, the filtered data will be returned; if the filtering fails, FALSE will be returned.

Usage example of PHP filter_var() function

Example 1: Filter string

Output:

762588++

Description:FILTER_SANITIZE_NUMBER_INTmeans to delete all other characters except numbers and -.

Example 2: Verify IP address

You can use the filter_var() function to verify whether the specified ip address is valid.

Output:

127.0.0.1 是有效的IP地址

Example 3: Filter and verify email (email) addresses

The filter_var() function first starts from Remove all illegal characters from the variable containing the email address and then check if it is a valid email address:

Output:

148521425@qq.com 是一个有效的电子邮件地址

Example 4: Filter and verify URL

filter_var() function first removes all illegal characters from the URL and then checks if it is a valid URL:

Output:

//m.sbmmt.com 是一个有效的URL

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