Server Side Programming Articles - Page 2357 of 2650

The constant() function returns the value of a constant.Syntaxconstant(const)Parametersconst − The name of the constant to checkReturnThe constant() function returns the value of a constant and NULL if the constant is not defined.ExampleThe following is an example that defines a constant. Live DemoOutputThe following is the output.This is it!

The FILTER_CALLBACK constant calls a user defined function to filter the value.ReturnThe FILTER_CALLBACK constant does not return anything.ExampleThe following is an example that converts the case of a string. Here, existing function in PHP is taken. Live DemoOutputThe following is the output.demo text!

The FILTER_SANITIZE_URL constant removes all illegal URL characters from a string. It allows the following −$-_.+!*'(),{}|\^~[]`">

The FILTER_SANITIZE_STRIPPED constant encodes or strips unwanted characters.Options and FlagsFILTER_FLAG_NO_ENCODE_QUOTES − This flag does not encode quotesFILTER_FLAG_STRIP_LOW − Strips characters with ASCII value below 32FILTER_FLAG_STRIP_HIGH − Strips characters with ASCII value above 32FILTER_FLAG_ENCODE_LOW − Encodes characters with ASCII value below 32FILTER_FLAG_ENCODE_HIGH − Encodes characters with ASCII value above 32FILTER_FLAG_ENCODE_AMP − Encodes the & character to &ReturnThe FILTER_SANITIZE_STRIPPED constant does not return anything.Example Live DemoOutputThe following is the output.string(10) "Demo!text!"

The FILTER_SANITIZE_STRING constant deletes tags and encodes special characters from a string.FlagsFILTER_FLAG_NO_ENCODE_QUOTES − Do not encode quotesFILTER_FLAG_STRIP_LOW − Removes characters with ASCII value less than 32FILTER_FLAG_STRIP_HIGH − Removes characters with ASCII value greater than 127FILTER_FLAG_ENCODE_LOW − Encodes characters with ASCII value less than 32FILTER_FLAG_ENCODE_HIGH − Encodes characters with ASCII value greater than 127FILTER_FLAG_ENCODE_AMP − Encodes the "&" character to &ReturnThe FILTER_SANITIZE_STRING constant does not return anything.Example Live DemoOutputThe following is the output.Demo!

The FILTER_SANITIZE_SPECIAL_CHARS constant filter HTML-escapes special characters.FlagsFILTER_FLAG_STRIP_LOW − Strip characters with ASCII value below 32FILTER_FLAG_STRIP_HIGH − Strip characters with ASCII value above 32FILTER_FLAG_ENCODE_HIGH − Encode characters with ASCII value above 32ReturnThe FILTER_SANITIZE_SPECIAL_CHARS constant does not anything.Example Live DemoOutputThe following is the output.string(43) "Favorite Sports is Football & Cricket?"

The FILTER_SANITIZE_NUMBER_INT constant deletes all illegal characters from a number.ReturnThe FILTER_SANITIZE_NUMBER_INT constant does not return anything.Example Live DemoOutputThe following is the output.string(5) "4-5+9"

The FILTER_SANITIZE_NUMBER_FLOAT constant deletes all illegal characters from a float number.FlagsFILTER_FLAG_ALLOW_FRACTION − Allows fraction separatorFILTER_FLAG_ALLOW_THOUSAND − Allows thousand separatorFILTER_FLAG_ALLOW_SCIENTIFIC − Allows scientific notationReturnThe FILTER_SANITIZE_NUMBER_FLOAT constant does not return anything.ExampleThe following is an example that use FILTER_FLAG_ALLOW_FRACTION flag. Live DemoOutputThe following is the output.string(8) "3-1+2.56"Let us see another example. Here, FILTER_FLAG_ALLOW_THOUSAND flag is used −Example Live DemoOutputHere is the output.string(8) "1-4+25,6"

The FILTER_SANITIZE_MAGIC_QUOTES constant performs the addslashes() function to a string. It adds backslashes in front of predefined characters i.e. single quote ('), double quote ("), backslash (\), NULL.ReturnThe FILTER_SANITIZE_MAGIC_QUOTES constant does not return anything.Example Live Demo

The FILTER_SANITIZE_ENCODED constant encodes special characters.Flags and OptionsFILTER_FLAG_STRIP_LOW − Remove characters with ASCII value less than 32FILTER_FLAG_STRIP_HIGH − Remove characters with ASCII value greater than 127FILTER_FLAG_ENCODE_LOW − Encode characters with ASCII value less than 32FILTER_FLAG_ENCODE_HIGH − Encode characters with ASCII value greater than 127ReturnThe FILTER_SANITIZE_ENCODED constant does not return anything.ExampleThe following is an example that use FILTER_FLAG_ENCODE_HIGH flag to encode characters with ASCII value > 127Example Live DemoOutputThe following is the output.www.example.comLet us see another example.Example Live DemoOutputHere is the output.example.comRead More