Python For All: **kwargs(Keyword arguments)

**kwargs(Keyword arguments):

Example 1:

def f1(*a):

print("a=",a)

#*args=("Hyd","vij","Kadapa")#creating tuple and storing into args var

f1(5) #valid output: a=5 since we can send non keyword argument

f1(a=5)#error we can not send keyword argument to the function

Example 2:

def f1(**args):

print("a=",args)

#f1(5)# error due to non keyword argument

f1(a=5)#valid as it is keyword output: a={1,5} in the form of dictionary

Python passes variable length non keyword argument to the function using *args but we cannot use this to pass keyword argument. For this problem Python has got a solution called **kwargs, it allows us to pass the variable length of keyword arguments to the function.

We use the double asterisk ** before the argument (parameter). The arguments are passed as a dictionary and these arguments make a dictionary inside function with name same as the parameter excluding double asterisk **.

Example 3: Using **kwargs to pass the variable keyword arguments to the function

def student(**data):

print("\nData type of argument:",type(data))

for key, value in data.items():

print("{} is {}".format(key,value))

student(name="Sita", Age=22, Phone=1234567890)

#student(name="Ram", Email="ram@gmail.com", course="MCA", Age=25, Phone=9876543210)

"""output:

Data type of argument: <class 'dict'>

name is Sita

Age is 22

Phone is 1234567890

>>>

"""

*args and *kwargs are special keyword which allows function to take variable length argument.

*args passes variable number of non-keyworded arguments list and on which operation of the list can be performed.

**kwargs passes variable number of keyword arguments dictionary to function on which operation of a dictionary can be performed.

*args and **kwargs make the function flexible.

def display(a,** kwarg):#**kwarg can take 0 or more values to display given values

print("fp",a)

for i,j in kwarg.items():

#items() gives pairs of item

print('key={},value={}'.format(i,j))

"""

Insteag of kwarg,we can give any identifier

output:

1. >>> display(2,rno=5)

fp 2

key=rno,value=5

>>>

2.>>> display(3,rno=4,name='ramesh')

fp 3

key=rno,value=4

key=name,value=ramesh

>>>

"""

In Python Dictionary, items() is used to return the list with all dictionary keys and values.

Syntax: dictionary.items()

Parameters: This method takes no parameters.

str.format() is one of the string formatting methods in Python3, which allows multiple substitutions and value formatting. This method lets us concatenate elements within a string through positional formatting.

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