args and kwargs

Fatma Kahveci
Coding
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  • We use *args and **kwargs as an argument when we do not know in advance the number of arguments that will be passed in the functions.
  • We can pass a variable number of arguments to a function using two special symbols:
    • *args := non-keyword arguments
    • **kwargs := keyword arguments

*args

  • It passes a variable number of non-keyworded arguments list and on which operation of the list can be performed.
def greet(*names):
    """This function greets all the persons in the names tuple."""

    for name in names:
        print("Hello", name)

greet("Bob", "Alice") # Hello Bob \n Hello Alice

greet("Bob") # Hello Bob

**kwargs

  • It passes a variable number of keyword arguments dictionary to function on which operation of a dictionary can be performed.
def intro(**data):
    print("Data type of argument:", type(data))

    for key, value in data.items():
        print("{} is {}".format(key, value))

intro(Firstname="Sita", Lastname="Sharma", Age=22, Phone=1234567890)
intro(Firstname="John", Lastname="Wood", Email="[email protected]", Country="Wakanda", Age=25, Phone=9876543210)

# Data type of argument: <class 'dict'>
# Firstname is Sita
# Lastname is Sharma
# Age is 22
# Phone is 1234567890

# Data type of argument: <class 'dict'>
# Firstname is John
# Lastname is Wood
# Email is [email protected]
# Country is Wakanda
# Age is 25
# Phone is 9876543210

Using *args and **kwargs in same line to call a function

  • At first, you should write *args.
def myFun(*args, **kwargs):
    print("args: ", args)
    print("kwargs: ", kwargs)

myFun('geeks', 'for', 'geeks', first="Geeks", mid="for", last="Geeks")
# args: ('geeks', 'for', 'geeks')
# kwargs {'first': 'Geeks', 'mid': 'for', 'last': 'Geeks'}

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