I was using code from this site (Pandas CSV output only the data in a certain row (to_csv)) to write a dataframe row to a csv row:
df.iloc[-1].to_csv('output.csv', mode='a', index=False, header=False)
but the result is
1
2
3
4
5
instead of
1, 2, 3, 4, 5
What is wrong here?
I want to make this work with df.to_csv and I've tried a few options. I know I could use different code such as with open(...) but the open() function conflicts with another list variable that I cannot change.
in your solution, you are getting pd.Series so you cant get the desired result. But the below solution will return you a pd.DataFrame row, so i think you can get what you want.
df.iloc[-1:].to_csv('output.csv', mode='a', index=False, header=False)
df.iloc[-1] gives you a pd.Series whose separate value is analogues to pd.DataFrame row with a single column, and that's how it's exported into your output csv (each value on a separate line).
To get the expected result you need to transform your Series into a DataFrame with one record/row and that's could be achieved in 2 ways:
"long" way: pd.DataFrame(columns=df.iloc[-1].index, data=[df.iloc[-1]]).to_csv('output.csv', mode='a', header=False, index=False)
short way: df.iloc[-1].to_frame().T.to_csv('output.csv', mode='a', header=False, index=False)
