#範例11-7：讀取cost.xlsx，計算新欄位=單價（支出金額/數量）
import pandas as pd
df = pd.read_excel('cost.xlsx','sheet')

print(df)

#新增一個欄位=單價
df['單價'] = df['支出金額']/df['數量']

#印出表格：[說明，單價]
print('印出表格：[說明，單價]=\n',df[['說明','單價']])