CODEWITHSUNDEEP
listpython-3.xif-statementfor-loopaverage
Lenard
Lenard

Reputation: 821

Finding the average of a list

So, guys I've got some code that reads a file:

lenard  1
lenard  1
lenard  10
max 3
max 3
max 3
zack    5
zack    5
zack    5
james   10
james   10
james   10

From the file a list is created in the form [10,10,10]. After this is done I calculate the average of the list and outputs it on the screen.

My code only partially works and does this instead:

10
18
28

and the average that it finds not the one for the list last_3_scores.

My question is why does the first number in the list keep on getting added together and the average of that is calculated instead of the average of last_3_scores.

Heres my code:

with open('StudentsScoreA.txt', "r+") as file:
    file.seek(0)
    scores = file.readlines()

scores_pairs = [score.strip().split('\t') for score in scores]
avg_with_name=[]
avg=[]
name_list=[]
last_3_scores=[]



for score in reversed(scores_pairs):
    name=score[0]
    name_list.append(name)

    for item in name_list:
        if name_list.count(name) > 1:
            name_list.remove(name)
            print(name_list)

for item in name_list:
    for score in reversed(scores_pairs):
        name=score[0]

        if name == item and len(last_3_scores) <= 3:
            last_3_scores.append(score[1])

        elif len(last_3_scores) == 3:
            print(last_3_scores)

    for items in last_3_scores:
        item=int(items)
        avg.append(item)
        print(sum(avg))
        mean=sum(avg)/len(last_3_scores)
        avg_with_name.append([name,mean])
        del last_3_scores[:]


for name, average in reversed(avg_with_name):
    print('{} your average was {}'.format(name,average))

Upvotes: 0

Views: 571

Answers (2)

Mike M&#252;ller
Mike M&#252;ller

Reputation: 85442

I would recommend doing something like this:

data = {}
with open('scores.txt') as fobj:
    for line in fobj:
        name, score = line.split()
        data.setdefault(name, []).append(int(score))

for name, scores in data.items():
    avg = sum(scores[-3:]) / min(3, len(scores))
    print('{} your average was {}'.format(name, avg))

Output:

james your average was 10.0
zack your average was 5.0
max your average was 3.0
lenard your average was 4.0

Sorted by average; highest first:

from operator import  itemgetter

for name, scores in sorted(data.items(), key=itemgetter(1), reverse=True):
    avg = sum(scores[-3:]) / min(3, len(scores))
    print('{} your average was {}'.format(name, avg))

Output:

james your average was 10.0
zack your average was 5.0
max your average was 3.0
lenard your average was 4.0

Upvotes: 1

Sede
Sede

Reputation: 61225

You can also use the defaultdict class from the collections module and the mean function from the statistics module.

Demo:

>>> from collections import defaultdict
>>> from statistics import mean
>>> data = defaultdict(list)
>>> with open('score.txt') as f:
...     for line in f:
...         name, score = line.split()
...         data[name].append(float(score))
...
...
>>> data
defaultdict(<class 'list'>, {'zack': [5.0, 5.0, 5.0], 'james': [10.0, 10.0, 10.0], 'max': [3.0, 3.0, 3.0], 'lenard': [1.0, 1.0, 10.0]}
>>> for name, score in data.items():
...     print('{} your average was {}'.format(name, mean(score)))
... 
zack your average was 5.0
james your average was 10.0
max your average was 3.0
lenard your average was 4.0

Upvotes: 0

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