lambda arguments: expression
- This function can have any number of arguments but only one expression, which is evaluated and returned.
- One is free to use lambda functions wherever function objects are required.
- You need to keep in your knowledge that lambda functions are syntactically restricted to a single expression.
- It has various uses in particular fields of programming besides other types of expressions in functions.
# Example
def cube(y):
return y*y*y;
g = lambda x: x*x*x
print(g(7))
print(cube(5))
Using lambda with...
# filter() with lambda()
li = [5, 7, 22, 97, 54, 62, 77, 23, 73, 61]
final_list = list(filter(lambda x: (x%2 != 0) , li))
print(final_list)
# map() with lambda()
li = [5, 7, 22, 97, 54, 62, 77, 23, 73, 61]
final_list = list(map(lambda x: x*2 , li))
print(final_list)
# reduce() with lambda()
from functools import reduce
li = [5, 8, 10, 20, 50, 100]
sum = reduce((lambda x, y: x + y), li)
print (sum)
Map
map(fun, iter)
def addition(n):
return n + n
# We double all numbers using map()
numbers = (1, 2, 3, 4)
result = map(addition, numbers)
print(list(result))
# Double all numbers using map and lambda
numbers = (1, 2, 3, 4)
result = map(lambda x: x + x, numbers)
print(list(result))
# Add two lists using map and lambda
numbers1 = [1, 2, 3]
numbers2 = [4, 5, 6]
result = map(lambda x, y: x + y, numbers1, numbers2)
print(list(result)) # [5, 7, 9]
# List of strings
l = ['sat', 'bat', 'cat', 'mat']
# map() can listify the list of strings individually
test = list(map(list, l))
print(test)
# [['s', 'a', 't'], ['b', 'a', 't'], ['c', 'a', 't'], ['m', 'a', 't']]
