add value to first cell in a new df column in python

Asked Aug 23 '21 at 14:43

Active Aug 23 '21 at 14:43

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I have the below code which adds the value across every cell but what i want is to create a new column called one_way_turnover and only add the value to the first cell not every cell. can someone help me please?

df[:, 'one_way_turnover'] = (df[col_name].abs.sum()) / 2

asked Aug 23 '21 at 14:43

Zack

Please refer to the answer for [this question](https://stackoverflow.com/questions/13842088/set-value-for-particular-cell-in-pandas-dataframe-using-index). – nismotri Aug 23 '21 at 14:46
what do you want to have in the other cells? NaNs, emptry strings? – luigigi Aug 23 '21 at 14:48
i tried this but doesn't work as its not a pre existing column – Zack Aug 23 '21 at 14:48
nan please if possible – Zack Aug 23 '21 at 14:49
then try sth like this `df['one_way_turnover'] = np.nan; df['one_way_turnover'].iloc[0] = (df[col_name].abs.sum()) / 2` – luigigi Aug 23 '21 at 14:52
legend, thanks a lot! – Zack Aug 23 '21 at 14:56

add value to first cell in a new df column in python

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