CODEWITHSUNDEEP
pythoncsvdictionary
Tim
Tim

Reputation: 43

Grouping data from a csv file in a dictionary

I currently have a csv file that holds a user's name and their score on a quiz (out of 10). The csv file looks like this:

Ben,8
Tim,9
Tim,10
Ben,10
Ben,9
Tim,7

I would like to group the data in a dictionary so a user's name is entered only once and so that it can hold all the user's scores on the quiz (as far as I am aware it is not possible to do in a csv file). The dictionary should look like this: 

scores = {'Ben': [8, 10, 9], 'Tim': [9, 10, 7], etc...}

How can I group the data from the csv file into a dictionary in this way?

I have tried searching for a key e.g. 'Ben' in the dictionary however it only returns the most recent score by 'Ben' in the CSV file.

Many thanks.

Upvotes: 0

Views: 275

Answers (2)

Vinod Sharma
Vinod Sharma

Reputation: 883

Have a look at the following example using defaultdict:

from collections import defaultdict
d = defaultdict(list)
with open('data.csv') as data:
    for line in data:
        name, score = line.strip("\n").split(',')
        d[name].append(int(score))

print d

Output:

defaultdict(<type 'list'>, {'Tim': [9, 10, 7], 'Ben': [8, 10, 9]})

Upvotes: 3

user648852
user648852

Reputation:

Here is an example:

sc_txt='''\
Ben,8
Tim,9
Tim,10
Ben,10
Ben,9
Tim,7'''

import csv

scores={}
for line in csv.reader(sc_txt.splitlines()):
    scores.setdefault(line[0], []).append(line[1])

print scores 
# {'Tim': ['9', '10', '7'], 'Ben': ['8', '10', '9']}

Just replace sc_txt.splitlines() with an open file object and you are golden.

Upvotes: 0

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