PHP advanced filter

Use filterDetect whether a number is within a range

The following example uses the filter_var() function to Check whether an INT type variable is within the range of 1 to 200:

 array("min_range"=>$min, "max_range"=>$max))) === false) { echo("变量值不在合法范围内"); } else { echo("变量值在合法范围内"); } ?>

Program running result:

The variable value is within the legal range Inside

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Detect IPv6 address

★FILTER_VALIDATE_IPThe filter validates the value as an IP.

The following example uses the filter_var() function to detect whether a $ip variable is an IPv6 address:

Program running result:

2001:0db8:85a3:08d3:1319:8a2e:0370:7334 is an IPv6 address

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Detect URL - must contain QUERY_STRING (query string)

QUERY_STRINGLiteral meaning It is the query string. For example, common URL web addresses have xxx.asp?pn=123456? What follows the number is querystring

The following example uses the filter_var() function to detect whether $url contains the query string:

Program running result:

http://www.baidu.com is not a legal URL

above The Url URL in the example does not contain QUERY_STRING, so the running result is a negative answer

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Remove characters with ASCII values greater than 127

★FILTER_SANITIZE_STRINGFilter removes or encodes unwanted characters.

The following example uses the filter_var() function to remove characters with an ASCII value greater than 127 in the string. It can also remove HTML tags:

Hello WorldÆØÅ!"; $newstr = filter_var($str, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_HIGH); echo $newstr; ?>

Program running results:

Hello World!

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PHP Filter Reference Manual

You can too View the specific application of filters by visiting the PHP Filter Reference Manual on this site.

The reference manual contains a brief description and usage examples of filter parameters!