我有一個(gè)從 DataFrame 創(chuàng)建的數(shù)據(jù)透視表。它基本上顯示了一個(gè)城市一周中每一天的請(qǐng)求數(shù)量。          M  T  W  T  F  S  SCITY 1     CITY 2CITY 3我想創(chuàng)建一個(gè)新列，用星期六的數(shù)字除以星期一、星期二、星期三和星期四的平均值。這是我寫的代碼，但是很笨拙。pivot_requests_per_area = df.pivot_table(values="requests_per_area", index="city name", columns="day", aggfunc=np.sum)pivot_requests_per_area["delta_sat"] =pivot_requests_per_area["Saturday"] / ((pivot_requests_per_area["Monday"]+pivot_requests_per_area["Tuesday"]+pivot_requests_per_area["Wednesday"]+pivot_requests_per_area["Thursday"])/4)我嘗試這樣做，但我從 err 中得到了引發(fā) KeyError(key) 的錯(cuò)誤。weekdays = pivot_requests_per_area["Monday", "Tuesday", "Wednesday", "Thursday"]pivot_requests_per_area["delta_fri"] =pivot_requests_per_area["Friday"] / pivot_requests_per_area[weekdays].mean()我想知道是否有比單獨(dú)添加列更有效的方法？