023_透视表_分组_聚合

import pandas as pd
import numpy as np

if __name__ == ‘__main__‘:
    pd.options.display.max_columns = 999
    orders = pd.read_excel("C:/Users/18124/Desktop/pandas/023_透视表_分组_聚合/Orders.xlsx")
    print(orders.head())

    # 显示列类型 - 日期
    print(orders.Date.dtype)    # 查看类型

    # 添加新列 - 年份
    orders["Year"] = pd.DatetimeIndex(orders["Date"]).year
    print(orders.head())


    # 方法一 : 透视表
    pt1 = orders.pivot_table(index="Category", columns="Year", values="Total", aggfunc=np.sum)
    print(pt1)

    # 方法二 :
    groups = orders.groupby(["Category", "Year"])
    s = groups["Total"].sum()
    c = groups["ID"].count()
    pt2 = pd.DataFrame({"Sum":s, "Count":c})
    print(pt2)