===============================================================================0
导入模块
>>> import pandas as pd
>>> with open("../pivot.py", "rt", encoding="utf8") as fp: exec(fp.read())
>>> df = pd.DataFrame({"A": ["foo", "foo", "foo", "foo", "foo", "bar", "bar", "bar", "bar"], "B": ["one", "one", "one", "two", "two", "one", "one", "two", "two"], "C": ["small", "large", "large", "small", "small", "large", "small", "small", "large"], "D": [1, 2, 2, 3, 3, 4, 5, 6, 7], "E": [2, 4, 5, 5, 6, 6, 8, 9, 9]})
===============================================================================1
给定index, columns和values，单个聚合函数
>>> print(df)
>>> res = pivot(df, values='D', index=['A', 'B'], columns=['C'], aggfunc="sum")
>>> print(res)
===============================================================================2
给定index, 和values，多个聚合函数
>>> print(df)
>>> res = pivot(df, values=['D', 'E'], index=['A', 'C'], aggfunc={'D': "mean", 'E': "mean"})
>>> print(res)
===============================================================================3
不同的列给定不同的聚合函数
>>> print(df)
>>> res = pivot(df, values=['D', 'E'], index=['A', 'C'], aggfunc={'D': "mean", 'E': ["min", "max", "mean"]})
>>> print(res)
===============================================================================4
添加边际统计量
>>> print(df)
>>> res = pivot(df, values=['D', 'E'], index=['A', 'C'], aggfunc="var", margin=1)
>>> print(res)
===============================================================================5
添加边际统计量，给定名称
>>> print(df)
>>> res = pivot(df, values=['D', 'E'], index=['A', 'C'], aggfunc="var", margin=1, margin_name="方差")
>>> print(res)
===============================================================================6
