combine multiple values in Python

Question

I have the data in the following format (in csv file):

 id, review
 1, the service was great!
 1, staff was friendly.
 2, nice location
 2, but the place was not clean
 2, the motel was okay
 3, i wouldn't stay there next time
 3, do not stay there

I would like to change the data to the following format:

 1, the service was great! staff was friendly. 
 2, nice location but the place was not clean the motel was okay
 3, i wouldn't stay there next time do not stay there

Any help would be appreciated.

What have you done so far? What is the matching criteria since the last line does not start with 1 but is appended to the lines before? — albert
– albert, Commented Sep 3, 2015 at 19:09

tobias_k · Accepted Answer · 2015-09-03 19:43:58Z

1

You can use itertools.groupby for grouping consecutive entries that have the same number.

import itertools, operator, csv
with open("test.csv") as f:
    reader = csv.reader(f, delimiter=",")
    next(reader) # skip header line
    for key, group in itertools.groupby(reader, key=operator.itemgetter(0)):
        print key, ' '.join(g[1] for g in group)

Output:

1  the service was great!  staff was friendly.
2  nice location  but the place was not clean  the motel was okay
3  i wouldn't stay there next time  do not stay there

Note: The code for reading the file is assuming that it's an actual CSV file, with , delimiter:

id, review
1, the service was great!
...

answered Sep 3, 2015 at 19:43

tobias_k

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1 Comment

kevin Over a year ago

This is exactly what I was looking for.

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