CODEWITHSUNDEEP
pythonarrayslist
Andre Queen
Andre Queen

Reputation: 223

How to calculate the total of each list, in a list of lists Python

I have collected a list of lists, each list representing data from a single day. I need to find the SUM of these to calculate the total volume each day. I can only seem to add together each list, not an individual lists data.

Provides the total of all the lists, not each individual lists total.

for ele in range(0, len(y_pred)): 
    total = total + y_pred[ele] 


print (total)

Expected 18 outputs, each lists sum, not one output with a sum of everything.

Upvotes: 0

Views: 2282

Answers (4)

Ehsan
Ehsan

Reputation: 67

You can use sum in a for loop:

total = []   
for i in list_of_lists:
    total.append(sum(i))

print(total)

Upvotes: 1

Ben Quigley
Ben Quigley

Reputation: 727

First of all, you don't need to use this pattern in Python:

for ele in range(0, len(y_pred)):  # let's not use "ele" as a var name, btw. confusing
    total = total + y_pred[ele]

because you can just write:

for element in y_pred: 
    total = total + element

Anyway, you could use map as another poster suggested, but the simplest way is to just extend your existing pattern. Since you have a list within a list, you have two lists to iterate through:

for sub_list in mega_list:
    for element in sub_list:
        total += element

Upvotes: 2

President James K. Polk
President James K. Polk

Reputation: 41967

Just use sum.

[sum(x) for x in ll]

Upvotes: 1

Djaouad
Djaouad

Reputation: 22776

Use map and sum:

sums = list(map(sum, list_of_lists))

where list_of_lists is the list that contains other lists. Now, sums is a list containing the sum of each sub-list. To get the entire sum, use sum again with the new sums list:

sum(sums)

Upvotes: 2

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