How to split() each entry in a list into a new csv column

Question

I have the following code which is reading a list of folders from a directory, and dumping them into a csv file.

import os, csv

mylist = os.listdir("M:/")

with open("output.csv", 'w') as myfile:
    wr = csv.writer(myfile, lineterminator='\n')
    wr.writerows(([row] for row in mylist))

Which is working well. The folders in the directory are all named using this format:

abc_123456

And the output I'm trying to get is:

abc, 123456
def, 789012

etc.

I know that I need to use split() but I can't work out where it needs to go

Possible duplicate of [How to split a string into a list?](https://stackoverflow.com/questions/743806/how-to-split-a-string-into-a-list) — MEE, Nov 03 '17 at 15:45
can you show an example of the format of the output.csv file? — Cyzanfar, Nov 03 '17 at 15:46
@Cyzanfar It's opened in `w` mode... The file is empty. The expected output is clearly stated — OneCricketeer, Nov 03 '17 at 15:47
@OzgurVatansever that's done it it perfectly, thank you. I was trying to overcomplicate it by including [row]. — Mcam435, Nov 03 '17 at 15:50

OneCricketeer · Accepted Answer · 2017-11-03T15:52:51.797

3

Assuming row = "abc_123456", you need to split that on "_"

[row] is making a list of one string that you are writing as the row.

row.split("_") is how you would split the data. This returns a list already, so no need for [row.split("_")], for example

If you want to have ", " as the delimiter rather than only a comma, then you need to add that to the writer.

wr = csv.writer(myfile, delimiter=', ', lineterminator='\n')
wr.writerows(row.split('_') for row in mylist)

edited Nov 03 '17 at 15:52

answered Nov 03 '17 at 15:51

OneCricketeer

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Yeah, didn't see that – OneCricketeer Nov 03 '17 at 15:53
3

"This returns a list already, so no need for [row.split("_")], for example" This was the mistake I was making. Thank you for the explanation as to why that's not needed. – Mcam435 Nov 03 '17 at 15:54

score 2 · Answer 2 · answered Nov 03 '17 at 15:51

As @OzgurVatansever stated in the comment you can simply split on "_":

import os, csv
mylist = os.listdir("M:/")

with open("output.csv", 'w') as myfile:
    wr = csv.writer(myfile, lineterminator='\n')
    wr.writerows(row.split("_") for row in mylist)

Hope that helps. Thanks @OzgurVatansever.

How to split() each entry in a list into a new csv column

2 Answers2