how to convert a column of string to a list

Question

I have select a string column from a table. Now I want to take all the values and convert to a list of string. I used the following code but it does not work.

top_feature = rf_varimp[['variable']].values.tolist()
top_feature

the output is:

[['mrkd100006'], ['mrkd100005'], ['ccs2376'], ['ccs644'], ['ccs3262']]

what I expect for the output is something like:

['mrkd100006', 'mrkd100005', 'ccs2376', 'ccs644', 'ccs3262']

score 1 · Answer 1 · answered Sep 11 '18 at 22:20

1

Pandas series can be cast to lists directly

list(rf_varimp['variable'])

Out:
['mrkd100006', 'mrkd100005', 'ccs2376', 'ccs644', 'ccs3262']

answered Sep 11 '18 at 22:20

Hli

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score 0 · Accepted Answer · answered Sep 11 '18 at 21:53

0

You are returning a multi dimensional array by using

rf_varimp[['variable']].values.tolist()

Use the following instead

rf_varimp['variable'].values.tolist()

There is a subtle difference between rf_varimp[['variable']] and rf_varimp['variable'] in that one is a pandas.DataFrame and the latter is a pandas.Series. Knowing the difference will save you a lot of hassle in the future with other pandas operations.

answered Sep 11 '18 at 21:53

Alexander McFarlane

9,832
8
52
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so rf_varimp[['variable']] is a data frame and rf_varimp['variable'] is a series? – Gavin Sep 11 '18 at 22:14
yes exactly the case – Alexander McFarlane Sep 11 '18 at 22:20

how to convert a column of string to a list

2 Answers2