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

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.