I am trying to learn Pandas for DA and I have managed to figure out merge and merge 2 DF together, but I'm trying to sum a new column whilst column x != column y

merged_by_country["total_shows"] = merged_by_country["show_id"]   merged_by_country["count"] #(lambda x, y: x != y)
test = merged_by_country.copy()

def set_shows(df):
    for r in df.iloc:
        if r[1] == r[3]:
            r[-1] = r[1]
        else:
            r[-1] = r[1]   r[3]
    return df
set_shows(test)

But I'm getting 'SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame' which I want it to do, but whenever I call the DF again, nothing changes... even tried copying the df in the func then performing the loop and passing back the new copied df but nothing happens.

             country  show_id        first_country  count  total_shows
              Jordan        1               Jordan      1            2
         Philippines        1          Philippines      1            2
United Arab Emirates        1 United Arab Emirates      1            2
         Switzerland        1          Switzerland      1            2
             Senegal        1              Senegal      1            2

edited with the sample of merged_by_country dataframe.

CodePudding user response：

IIUC, you can use np.where:

# Renamed 'merged_by_country' to 'df' for readability
df['total_shows'] = np.where(df['show_id'] == df['count'],
                             df['show_id'],
                             df['show_id']   df['count']) 

CodePudding user response：

df['total_shows'] = df.show_id
idx = df[df.country!=df.first_country].index
df.loc[idx, 'total_shows'] = df.loc[idx, 'show_id']  df.loc[idx, 'count']