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

In php, variables do not need to be defined in advance, so in many cases, the php variable type is ambiguous, but php provides the gettype () function to obtain the variable type, it can determine all the variable types in php.

In php, variables do not need to be defined in advance, so in many cases, the php variable type is ambiguous, but php provides the gettype () function to obtain the variable type, he can determine all the variable types in php.

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 instance code is as follows:

2. // Returns string
3. $ Var = "hello ";
4. Echo gettype ($ var );
5. // Returns double
6. $ Var = 1000.56;
7. Echo gettype ($ var );
8. ?>

Warning

Do not use gettype () to test a certain 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 instance code is as follows:

1. $ A = "test ";
2. $ B = "anothertest ";
3. Echo isset ($ )? 'True': 'false ';

Output result: true

The instance code is as follows:

2. // Returns true
3. $ Var = "yes ";
4. Echo isset ($ var )? "True": "false ";
5. // Returns false
6. Echo isset ($ test )? "True": "false ";
7. ?>

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