Php obtains the variable type and determines whether it is a variable.

Source: Internet
Author: User

Variable types

Gettype ($ var)
This function returns the type of the variable. For example, "string", "integer", "boolean", and "floating point value. Before inserting a variable into a strictly typed database domain, this function is generally used to verify whether the variable is the expected type.

The code is as follows: Copy code

<? Php
// Returns string
$ Var = "hello ";
Echo gettype ($ var );
// Returns double
$ Var = 1000.56;
Echo gettype ($ var );
?>

Warning
Do not use gettype () to test a type, because the returned string may need to be changed in future versions. In addition, because it contains a string comparison, it runs slowly.

Use the is _ * function instead.

 
Check valid variables

Isset is used to determine whether a variable exists or not. If yes, true is returned. Otherwise, false is returned. This variable is very useful for us. We can determine whether a variable such as get post is present.

Isset instance"

The code is as follows: Copy code

$ A = "test ";
$ B = "anothertest ";

Echo isset ($ )? 'True': 'false ';

Output result: true

Instance 2

The code is as follows: Copy code

<? Php
// Returns true
$ Var = "yes ";
Echo isset ($ var )? "True": "false ";
// Returns false
Echo isset ($ test )? "True": "false ";
?>

The above are two super simple php functions, isset () and gettype (), which are no difficulty. For more information, see.

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