pythonarrayslist

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.


Solution

  • 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