2.7 Some built-in functions

Let's check some related built-in functions which we'll be needing later on such as type(), isinstance(), id() and dir().

1. type(object) => str

Parameters:

Explanation: This function is used for type checking, it returns the class name of an object.

a = "What?"
print(type(a)) # str
b = 5.0
print(type(b)) # float

2. isinstance(object, class) => bool

Parameters:

Explanation: This function checks if an object is an instance of a particular class. Returns True/False.

a = 23
print(isinstance(a, int)) # True
print(isinstance(a, float)) # False
print(isinstance(a, str)) # False

3. id(object) => int

Parameters:

Explanation: This function returns the object's identity (id) and every object has a unique id. The identity is simply the representation of an object's address in the memory (where it is stored). The returned object's id varies across programs/systems, so will not be the same anytime.

my_float = 50.0
print(id(my_float)) # 1875526208176

4. dir(object) => list

Parameters:

Explanation: Returns a list containing names of variables in an object and functions supported by that object.

## Names under current local scope
print(dir())


## List of object's attributes
print(dir(int))
print(dir(str))