Pandas: Dataframe.Drop - ValueError: labels ['id'] not contained in axis

Question

Attempting to drop a column from a DataFrame in Pandas. DataFrame created from a text file.

import pandas as pd 
df = pd.read_csv('sample.txt')
df.drop(['a'], 1, inplace=True)

However, this generates the following error:

ValueError: labels ['a'] not contained in axis      

Here is a copy of the sample.txt file :

a,b,c,d,e
1,2,3,4,5
2,3,4,5,6
3,4,5,6,7
4,5,6,7,8

Thanks in advance.

Answer 1

So the issue is that your "sample.txt" file doesn't actually include the data you are trying to remove.

Your line

df.drop(['id'], 1, inplace=True) 

is attepmting to take your DataFrame (which includes the data from your sample file), find the column where the value is 'id' in the first row (axis 1) and do an inplace replace (modify the existing object rather than create a new object missing that column, this will return None and just modify the existing object.).

The issue is that your sample data doesn't include a column with a header equal to 'id'.

In your current sample file, you can only to a drop where the value in axis 1 is 'a', 'b', 'c', 'd', or 'e'. Either correct your code to drop one of those values or get a sample files with the correct header.

The documentation for Pandas isn't fantastic, but here is a good example of how to do a column drop in Pandas: http://chrisalbon.com/python/pandas_dropping_column_and_rows.html

** Below added in response to Answer Comment from @saar

Here is my example code: Sample.txt:

a,b,c,d,e
1,2,3,4,5
2,3,4,5,6
3,4,5,6,7
4,5,6,7,8

Sample Code:

import pandas as pd

df = pd.read_csv('sample.txt')
print('Current DataFrame:')
print(df)
df.drop(['a'], 1, inplace=True)
print('\nModified DataFrame:')
print(df)

Output:

>>python panda_test.py
Current DataFrame:
   a  b  c  d  e
0  1  2  3  4  5
1  2  3  4  5  6
2  3  4  5  6  7
3  4  5  6  7  8

Modified DataFrame:
   b  c  d  e
0  2  3  4  5
1  3  4  5  6
2  4  5  6  7
3  5  6  7  8

Answer 2

bad= pd.read_csv('bad_modified.csv')
A=bad.sample(n=10)
B=bad.drop(A.index,axis=0)

This is an example of dropping a dataframe partly. In case you need it.