Skip to content

Instantly share code, notes, and snippets.

@aculich
Last active April 5, 2022 16:57
Show Gist options
  • Star 15 You must be signed in to star a gist
  • Fork 5 You must be signed in to fork a gist
  • Save aculich/fb2769414850d20911eb to your computer and use it in GitHub Desktop.
Save aculich/fb2769414850d20911eb to your computer and use it in GitHub Desktop.
remove-empty-columns
foo bar baz
a 1
b 2
c
4
e 5
Display the source blob
Display the rendered blob
Raw
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
#!/usr/bin/env python
# coding: utf-8
# To drop all empty columns (but still keeping the headers) using the Python [Pandas library](http://pandas.pydata.org/) we can use the following 4-line script to read in the csv file, drop the columns where **all** the elements are missing, and save the data to a new csv file.
# In[1]:
from pandas.io.parsers import read_csv
data = read_csv('remove-empty-columns.csv')
filtered_data = data.dropna(axis='columns', how='all')
filtered_data.to_csv('empty-columns-removed.csv', index=False)
# As shown below, the sample data included in the csv file has 3 columns which contain missing values.
#
# The second column, labeled **bar**, is completely empty except the header; columns like this should be dropped. The other columns contain data, but should not be dropped even though they contain some missing values.
# In[2]:
data
# Using the [pandas.DataFrame.dropna()](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.dropna.html) function with the **columns** axis we can drop any column where **all** the entries are **NaN** (missing values).
# In[3]:
filtered_data = data.dropna(axis='columns', how='all')
filtered_data
@EricPeter
Copy link

It works thanx

@ganeshan
Copy link

The statement
filtered_data.to_csv('empty-columns-removed.csv')
will write first column with index values and the column header will be empty. To prevent writing index column, use this code instead.
filtered_data.to_csv('empty-columns-removed.csv', index=False)
Thanks very much for the script.

@JayProXter
Copy link

doesn't work for me ;(

@zhixe
Copy link

zhixe commented Mar 18, 2021

doesn't work for me :(

@aculich
Copy link
Author

aculich commented Mar 18, 2021

@zhixe @JayProXter i've updated the script based on the suggestion from @ganeshan

Does it work for you now? If not, can you let me know what errors or unexpected behaviors you are seeing?

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment