How should I check to see a if value exists in PHP?

The开发者_运维知识库re are many ways to see if a value exists using PHP. There's isset, !=false, !==false, !empty, etc. Which one will be the best (fast and accurate) one to use in the following situation?

if($_GET['test'])
...

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if (isset($_GET['test'])) { // use value }

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if(array_key_exists($_GET, "test"))

array_key_exists return true if a key exists in an array, isset will return true if the key/variable exists and is not null.

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Isset is probably best because it checks if the url contains a "?test=". If you want to make sure it is not empty you have to check further.

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I'd go with the php5 one type of get:

$test = filter_input(INPUT_GET, 'test', FILTER_SANITIZE_STRING);
if($test){
  //do something
}

Reference here, you can validate and sanitize with them. you can use "filter_input_array" for the full input types.

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isset function only checks for its avaliability you have to use empty function too in order to see if it is set and not empty also as:

if (isset($_GET['test']) && !empty($_GET['test'])) {