CODEWITHSUNDEEP
pythonlistdictionaryaverage
Aminoff
Aminoff

Reputation: 717

Average values of integer lists and dictionaries

Is there a way of calculating the average of the values of two or more lists or even dictionaries?

This is what I came up with:

lista = [1, 2, 3, 4, 5]
listb = [5, 4, 3, 2, 1]

listavg = [0]*5
count = 0
for i in lista:
    listavg[count] = (i + listb[count]) / 2
    count += 1

print(listavg)

[3.0, 3.0, 3.0, 3.0, 3.0]

But what if I have 100 lists? And what if those lists are inside dictionaries like these:

{'A': [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 'B': [1, 1, 1, 1, 1, 1, 1, 1, 1, 1], 'C': [2, 2, 2, 2, 2, 2, 2, 2, 2, 2], 'D': [3, 3, 3, 3, 3, 3, 3, 3, 3, 3], 'E': [4, 4, 4, 4, 4, 4, 4, 4, 4, 4], 'F': [5, 5, 5, 5, 5, 5, 5, 5, 5, 5], 'G': [6, 6, 6, 6, 6, 6, 6, 6, 6, 6], 'H': [7, 7, 7, 7, 7, 7, 7, 7, 7, 7], 'I': [8, 8, 8, 8, 8, 8, 8, 8, 8, 8], 'J': [9, 9, 9, 9, 9, 9, 9, 9, 9, 9]}

P.S. the length of the list is always the same.

EDIT: Important note is that I want the average of each index, not the average of the list.

Upvotes: 1

Views: 131

Answers (3)

Aran-Fey
Aran-Fey

Reputation: 43146

Use zip and a list comprehension:

>>> [sum(l)/len(l) for l in zip(*list_dict.values())]
[4.5, 4.5, 4.5, 4.5, 4.5, 4.5, 4.5, 4.5, 4.5, 4.5]

Upvotes: 4

Krohnus Melavea
Krohnus Melavea

Reputation: 152

lista = [1, 2, 3, 4]
listb = [5, 6, 7, 8, 9]
lists = lista + listb
average = sum(lists) / len(lists)

I think this works fine.

Upvotes: 0

Chris
Chris

Reputation: 22953

You can use zip() to get a tuple of each element grouped together index-wise from the input lists, and use sum() to add them together:

>>> def averages(*lists):
    return [sum(els) / len(els) for els in zip(*lists)]

>>> averages([1, 2, 3, 4, 5], [5, 4, 3, 2, 1])
[3.0, 3.0, 3.0, 3.0, 3.0]
>>>

Upvotes: 1

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