reduce()

reduce(function, iterable[, initializer])

from functools import reduce

numbers = [3, 4, 6, 9, 34, 12]

def custom_sum(first, second):
    return first + second

result = reduce(custom_sum, numbers)

# python code to demonstrate working of reduce() 
  
# importing functools for reduce() 
import functools 
  
# initializing list 
lis = [ 1 , 3, 5, 6, 2, ] 

# using reduce to compute sum of list 
print ("The sum of the list elements is : ",end="") 
print (functools.reduce(lambda a,b : a+b,lis)) 
  
# using reduce to compute maximum element from list 
print ("The maximum element of the list is : ",end="") 
print (functools.reduce(lambda a,b : a if a > b else b,lis))