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❖ What are Python Lambda functions?
❖ Why are they used?
❖ How to write Anonymous functions?
❖ Lambda functions within user defined functions
• filter()
• map()
❖ Using Anonymous functions within
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• reduce()
❖Solving Algebraic expressions using Lambda

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PythonLambda Functionsare:
• Anonymousornameless functions
• ‘lambda’isnotaname,butitsakeyword
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Also known as throw-
away functions as they
are needed just once
They are also passed
as inputs or returned
as outputs of other
higher-order functions
The body of Lambda
functions is written in
a single line
One-time use I/O of other functions Reduce code size
Why are they used?
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A Lambda function is created using the lambda
operator
lambda arguments: expression
lambda : “Specify the purpose”
lambda a1…n: “Specify use of a1…n“
lambda a1: “Specify use of a1“
SYNTAX:
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Lambda functions are best used within other higher-
order functions
Anonymous functions within
user defined functions
def new_func(x):
return(lambda y: x+y)
t=new_func(3)
u=new_func(2)
print(t(3))
print(u(3))
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filter()
Used to filter the given iterables(lists, sets, etc) with the help
of another function passed as an argument to test all the
elements to be true or false.
my_list = [2,3,4,5,6,7,8]
new_list = list(filter(lambda a: (a/3 == 2), my_list))
print(new_list)
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map():
Applies a given function to all the iterables and returns a
new list.
my_list = [2,3,4,5,6,7,8]
new_list = list(map(lambda a: (a/3 != 2), li))
print(new_list)
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reduce():
Applies some other function to a list of elements that are
passed as a parameter to it and finally returns a single
value.
from functools import reduce
reduce(lambda a,b: a+b, [23,21,45,98])
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Copyright © 2017, edureka and/or its affiliates. All rights reserved.
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