import pandas as pd

import numpy as np

dates = pd.date_range('20130101', periods=6)

df=pd.DataFrame(np.arange(24).reshape((6,4)),index=dates, columns=['A','B','C','D'])

# 行数，列数，赋值

df.iloc[1,2] = 1111

df.loc['20130101','B'] = 2222

print('-1-')

print(df)

df[df.A>4] = 0

print('-2-')

print(df)

df.A[df.A>4] = 0

print('-3-')

print(df)

# 添加列

df['F'] = np.nan

print('-4-')

print(df)

df['E'] = pd.Series([1,2,3,4,5,6],index=pd.date_range('20130101',periods=6))

print('-5-')

print(df)

-1-

             A     B     C   D

2013-01-01   0  2222     2   3

2013-01-02   4     5  1111   7

2013-01-03   8     9    10  11

2013-01-04  12    13    14  15

2013-01-05  16    17    18  19

2013-01-06  20    21    22  23

-2-

            A     B     C  D

2013-01-01  0  2222     2  3

2013-01-02  4     5  1111  7

2013-01-03  0     0     0  0

2013-01-04  0     0     0  0

2013-01-05  0     0     0  0

2013-01-06  0     0     0  0

-3-

            A     B     C  D

2013-01-01  0  2222     2  3

2013-01-02  4     5  1111  7

2013-01-03  0     0     0  0

2013-01-04  0     0     0  0

2013-01-05  0     0     0  0

2013-01-06  0     0     0  0

-4-

            A     B     C  D   F

2013-01-01  0  2222     2  3 NaN

2013-01-02  4     5  1111  7 NaN

2013-01-03  0     0     0  0 NaN

2013-01-04  0     0     0  0 NaN

2013-01-05  0     0     0  0 NaN

2013-01-06  0     0     0  0 NaN

-5-

            A     B     C  D   F  E

2013-01-01  0  2222     2  3 NaN  1

2013-01-02  4     5  1111  7 NaN  2

2013-01-03  0     0     0  0 NaN  3

2013-01-04  0     0     0  0 NaN  4

2013-01-05  0     0     0  0 NaN  5

2013-01-06  0     0     0  0 NaN  6