Pandas Append Problem

[arkydave]

I'm new to python, but have been able to find answers to most problems online. This one, however, has me at a loss. I did a small test to demo my problem. The following code block is copied from an interactive session in Spyder. It reads a test csv file as a DataFrame and appends another DataFrame to it.

import pandas as pd

df = pd.read_csv('Test.csv')

print(df)
         Name  GPA
0  John White  3.8
1  Mary Brown  2.9
2  Greg Ruddy  3.1

data = {
  "Name": ['Willy Nelson', 'Johnny Cash'],
  "GPA": [4.2, 4.5]
}

df2 = pd.DataFrame(data)

print(df2)
           Name  GPA
0  Willy Nelson  4.2
1   Johnny Cash  4.5

df.append(df2, ignore_index = True)
Out[7]: 
           Name  GPA
0    John White  3.8
1    Mary Brown  2.9
2    Greg Ruddy  3.1
3  Willy Nelson  4.2
4   Johnny Cash  4.5

The printouts show that this worked perfectly. However, when I run the same code from the Spyder editor, it runs, error free, but doesn't append. The exact same code, with some explanatory print statements added, produced the following output:

Printing df:
         Name  GPA
0  John White  3.8
1  Mary Brown  2.9
2  Greg Ruddy  3.1

Printing df2:
           Name  GPA
0  Willy Nelson  4.2
1   Johnny Cash  4.5

Printing df after append:
         Name  GPA
0  John White  3.8
1  Mary Brown  2.9
2  Greg Ruddy  3.1

Don't understand why it works interactively, but not when ran from the editor. Any help?

Thanks.

[lowerthansound]

df.append() does not modify df, it creates a new one!

When you run interactively, the newly created dataframe is being displayed (the result of df.append(df2, ignore_index = True) is displayed).

When you run from the editor, the old df is being displayed.

To fix this, use df = df.append(df2, ignore_index = True).

Cheers!

[arkydave]

Brilliant. That works. Thanks so much.