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Need to delete some specific column and rows(by index) of multiple csv files, without creating new files.

For the code below, it is giving output with new blank rows after each row.

import csv

with open('file.csv') as fd:
   reader = csv.reader(fd)
   valid_rows = [row for idx, row in enumerate(reader) if idx != 0]

with open('file.csv', 'w') as out:
   csv.writer(out).writerows(valid_rows)

What is the simpler way to do this(might be by other python libraries)?

Shaila Zaman
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1 Answers1

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Since you wish not to generate any new csv files and would like the data to perform operations, I would suggest you to make use of Pandas Framework. Make use of drop function in this framework.

Consider the following example:

Sample.csv:

col1,col2,col3,col4
1,2,3,4
5,6,7,8
9,10,11,12
13,14,15,16
17,18,19,20

Code:

import pandas as pd
df = pd.read_csv('./Sample.csv')

To delete columns:

df.drop('col3', axis = 1, inplace = True)

df contents:

   col1     col2    col4
0   1   2   4
1   5   6   8
2   9   10  12
3   13  14  16
4   17  18  20

To delete rows:

df.drop(df.index[[1,4]], inplace = True)

df contents:

   col1     col2    col4
0   1   2   4
2   9   10  12
3   13  14  16

Finally to save the edited csv file:

df.to_csv('new_sample.csv', index = False)
Prasad
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  • Hi, this solution is for reading data only. I need to make the changes(deleting rows& columns) on the csv files also. – Shaila Zaman Nov 24 '17 at 03:36
  • @ShailaZaman, make use of `inplace` option for that. I have edited the code. Check it out – Prasad Nov 24 '17 at 03:42
  • Please can you elaborate where df is becoming None? The code I have given is a working example. (Check if you are not deleting all columns or rows by mistake) – Prasad Nov 24 '17 at 04:06
  • That was a mistake by me. It is working. Thank you so much. Could you please edit your writing to csv line to the following line? df.to_csv('sample.csv', index=False) It was saving the csv with index of df. – Shaila Zaman Nov 24 '17 at 04:37