PHP Common type judgment function

1.gettype (): Gets the variable type 2.is_array (): Determines whether the variable type is an array type 3.is_double (): Determines whether the variable type is a double floating-point type 4.is_float (): Determines whether the variable type is floating-point type 5.is_int () : Determines whether the variable type is an integer type 6.is_integer (): Determines whether the variable type is a long integer type 7.is_long (): Determines whether the variable type is a long integer type 8.is_object (): Determines whether the variable type is an object type 9.is_real (): Determines whether the variable type is a real type 10.is_string (): Determines whether the variable type is a string type. 11.is_binary (): Finds Whether a variable is a native binary string
12.is_bool (): Detects if the variable is Boolean
13.is_dir (): Determines whether the given file name is a directory 14.is_file (): Determines whether the given file name is a normal file 15.is_null (): Detects if the variable is null 16:is_numeric (): Detects if a variable is a numeric or numeric string
17.is_resource (): Detects if a variable is a resource type
18.is_unicode (): Finds Whether a variable is a Unicode string. All of the above is used to detect whether a variable is a function of a certain format, is to return true, otherwise return false.