pandas SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame.
pandas : SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. どちらでも Warning: 1 2 3 4 5 6 def _balance(df): if df["bookitem_kind"] == "1": return -1 * df["amount"] return df["amount"] df_epm_cost["amount2"] = df_epm_cost.apply(_balance, axis=1) 1 df_epm_cost["amount"].where(df_epm_cost["bookitem_kind"] == "0", -1 * df_epm_cost["amount"], inplace=True) ValueError: cannot reindex on an axis with duplicate labels 1 df_epm_cost.loc[df_epm_cost["bookitem_kind"] == "1", "amount2"] = df_epm_cost["amount"] * (-1) FutureWarning: reindexing with a non-unique Index is deprecated and will raise in a future version ValueError: cannot reindex on an axis with duplicate labels インデックスを削除するとうまく行く: ...