pandas

数据结构

Series（一维）和DataFrame（二维）

Series

import numpy as np
import pandas as pd
s = pd.Series([2, 4, np.nan, 8])
print(s)
# 输出
0    2.0
1    4.0
2    NaN
3    8.0
dtype: float64

DataFrame

index（行）等于axis0，columns（列）等于axis1。

import numpy as np
import pandas as pd
dates = pd.date_range('20200101', periods=4)
random = np.random.randn(4, 4)
df = pd.DataFrame(random, index=dates, columns=['c1', 'c2', 'c3', 'c4'])
print(df)
                  c1        c2        c3        c4
2020-01-01 -1.423157  0.540590  1.752003 -0.368315
2020-01-02 -0.612663 -0.286877  0.696933 -1.793101
2020-01-03  0.082774  0.879219 -0.372299  0.804508
2020-01-04  1.058938  1.488765 -0.151950 -0.940176

#取一列
df['c2']
# 行切片
df[0:3]
df['20200101':'20200103']

参考

https://www.pypandas.cn/