pandas group分组

某列数据按照某列分组：

import numpy as np
import pandas as pd

df = pd.DataFrame({"key1": list("aabba"),
               "key2": ["one","two","one","two","one"],
               "data1": np.random.randn(5),  # 生成服从标准正态分布的随机数构成的一维数组
               "data2": np.random.randn(5)})
print(df)

grouped = df["data1"].groupby(df["key1"]) 
print(grouped.max())
print(grouped.min())
print(grouped.mean())
print(grouped.std())
print(grouped.describe())
# for loop all group
for name, group in grouped:
    print("name: {}".format(name))
    print("group:\n{}".format(group))

某列数据按照某几列分组：

grouped1 = df["data1"].groupby([df["key1"], df["key2"]]) 

所有数据按照某列分组：

grouped1 = df["data1"].groupby([df["key1"], df["key2"]]) 

按照数据类型划分列：

grouped3 = df.groupby(df.dtypes, axis=1)