# Prefix sum array in python using the accumulate function

PythonServer Side ProgrammingProgramming

Given an array and we have to do the prefix sum array using function.itertools.accumulate(iterable[, func]) module functions all construct and return iterators. So they should only be accessed by functions or loops that truncate the stream. Make an iterator that returns accumulated sums. Elements may be any addable type including Decimal or Fraction. If the optional function argument is supplied, it should be a function of two arguments and it will be used instead of addition.

## Example

Input:
Data = [1, 0, 2, 3, 5]
>>> list(accumulate(data))     # running summation
Output:
[1, 1, 3, 6, 11]


## Algorithm

Step 1: Create list.
Step 2: Use list(accumulate( ))) function, its return running total.
Step 3: Display total.


## Example Code

# Python program to print prefix
#sum array using accumulate function
from itertools import accumulate

def summation(A):
print ("The List after Summation ::>", list(accumulate(A)))

# Driver program
if __name__ == "__main__":
A=list()
n=int(input("Enter the size of the First List ::"))
print("Enter the Element of First  List ::")
for i in range(int(n)):
k=int(input(""))
A.append(k)
summation(A)


## Output

Enter the size of the First List ::5
Enter the Element of First List ::
1
2
3
4
5
The List after Summation ::> [1, 3, 6, 10, 15]

Updated on 30-Jul-2019 22:30:23