Help to get summation list of lists generated iteratively

Question

Help to get summation list of lists generated iteratively

Navigation

#1 by (2 votes)

2

I have developed a program with which I generate a list in each round of a total of 5 rounds. I add these lists to a list of lists called my_list_tot. The code is as follows:

import random

mi_lista_tot=[]

for round in range(5):
    mi_lista=[]
    mi_lista_tot.append(mi_lista)

    a1=[random.randrange(2) for i in range(8)]
    a2=[random.randrange(2) for i in range(8)]
    a3=[random.randrange(2) for i in range(8)]

    for n in range(len(a1)):
        mi_lista.append(a1[n] + a2[n] + a3[n])

print mi_lista_tot

In the current output, what I am generating is a list of lists of the following type:

[[2, 2, 1, 2, 2, 2, 2, 2], [2, 2, 1, 0, 1, 2, 0, 3], [2, 1, 2, 0, 1, 1, 3, 3], [2, 1, 2, 2, 1, 2, 2, 1], [1, 1, 2, 0, 0, 0, 0, 2]]

However, I would like my_list_tot to generate a summation list of the values in each index. In this case:

[9, 7, 8, 6, 5, 7, 7, 11]

It's what I can not do. I appreciate comments.

python python-2.7

asked by pyring 02.10.2017 в 22:35

source

1 answer

Problem with List string Repeatedly modify url based on a list and visit it

score 2 · Accepted Answer

Without modifying your code too much you can use zip or itertools.izip (which uses an iterator similar to what zip does in Python 3, decreasing the use of memory) next to sum to add a1 , a2 and a3 in each round and then add the rounds between themselves:

import itertools
import random

mi_lista_tot=[]

for round in range(5):
    a1=[random.randrange(2) for i in range(8)]
    a2=[random.randrange(2) for i in range(8)]
    a3=[random.randrange(2) for i in range(8)]

    mi_lista_tot.append([sum(x) for x in itertools.izip(a1,  a2, a3)])

mi_lista_tot = [sum(x) for x in itertools.izip(*mi_lista_tot)]
print mi_lista_tot

If you did not use a1 , a2 and a3 or the lists of each round for nothing else you could simply do:

import itertools
import random

mi_lista_tot = [sum(r) for r in itertools.izip(*[[random.randrange(2) for i in range(8)]
                                                    for _ in range (5*3)])]
print(mi_lista_tot)