How do I drop a column from multiple pandas dataframes using a loop?

Question

I have multiple dataframes in a list CGdfs.

CGdfs = [CGdf_2002, CGdf_2003, CGdf_2004, CGdf_2005, CGdf_2006, CGdf_2007, CGdf_2008, CGdf_2009, CGdf_2010, CGdf_2011, CGdf_2012, CGdf_2013, CGdf_2014, CGdf_2015, CGdf_2016, CGdf_2017, CGdf_2018]

I want to drop a column named 'Plot' from all these dataframes using a loop. How do I do this?

I have tried the below, this does not work

for df in CGdfs:
   df = df.drop('Plot', axis =1)

Please explain why it does not work. Do you get errors? Post the traceback — Valentino, May 23 '19 at 15:12
@anky_91 It does god's work - it removes a column but also returns it. Problem is you can only pop one at a time so it is limiting if you want to drop multiple columns. — cs95, May 23 '19 at 15:28

score 1 · Accepted Answer · edited May 23 '19 at 15:59

1

This should work:

for df in CGdfs:
    df.drop(columns = ['Plot'], inplace= True)

edited May 23 '19 at 15:59

cs95

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answered May 23 '19 at 15:13

Pasindu Gamarachchi

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Both of them are wrong. Can you figure out why? – cs95 May 23 '19 at 15:23
The first one does not appear to re-assign the new df(modified) to the df in the list. Second one seems to work(tested it out) – Pasindu Gamarachchi May 23 '19 at 15:55
1

Yes! Removed the incorrect answer from your post. – cs95 May 23 '19 at 15:59

score 1 · Answer 2 · answered May 23 '19 at 15:14

1

I think the problem is that it's not applying the drop to the original DataFrame object. Try:

for df in CGdfs:
    df.drop('Plot', axis=1, inplace=True)

When you inspect the elements of CGdfs the "Plot" column should be removed.

answered May 23 '19 at 15:14

iamchoosinganame

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How do I drop a column from multiple pandas dataframes using a loop?

2 Answers2