pandas基本操作2

Posted 2020-11-08 棍子哥

1、axes返回标签列表

import pandas as pd
import numpy as np
dates = pd.date_range(‘20170101‘, periods=8)
df = pd.DataFrame(np.random.randn(8,4), index=dates, columns=list(‘ABCD‘))
print("df:")
print(df)
print(‘-‘*50)
print ("The axes are:")
print (df .axes)
print (df.empty)#empty示例，返回布尔值，表示对象是否为空。返回True则表示对象为空

D:\Download\python3\python3.exe D:/Download/pycharmworkspace/s.py
df:
                   A         B         C         D
2017-01-01 -0.579966 -0.435075  0.308428 -0.684288
2017-01-02 -0.046761  0.209575  1.426686 -0.152909
2017-01-03  0.649144 -1.312502 -0.520895 -0.128796
2017-01-04  0.469305  0.738260  3.650268 -1.290882
2017-01-05  0.195328 -1.236598  0.245380 -0.845111
2017-01-06  0.886847 -0.946261 -0.884007 -0.527200
2017-01-07  1.002840  2.183883  0.709170 -0.618336
2017-01-08 -1.626558 -0.077388 -2.251855 -1.709279
--------------------------------------------------
The axes are:
[DatetimeIndex([‘2017-01-01‘, ‘2017-01-02‘, ‘2017-01-03‘, ‘2017-01-04‘,
               ‘2017-01-05‘, ‘2017-01-06‘, ‘2017-01-07‘, ‘2017-01-08‘],
              dtype=‘datetime64[ns]‘, freq=‘D‘), Index([‘A‘, ‘B‘, ‘C‘, ‘D‘], dtype=‘object‘)]

Process finished with exit code 0

2、empty示例，返回布尔值，表示对象是否为空。返回True则表示对象为空

print(df.empty)

3、

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2018/5/24 15:03
# @Author  : zhang chao
# @File    : s.py
from scipy import linalg as lg
#按标签选择
#通过标签选择多轴

import pandas as pd
import numpy as np
dates = pd.date_range(‘20170101‘, periods=8)
s = pd.DataFrame(np.random.randn(8,4), index=dates, columns=list(‘ABCD‘))
print("s:")
print(s)
print(‘-‘*50)
print ("The axes are 数据的标签:")
print (s .axes)
print ("The dimensions of the object 数据的维数:")
print (s.ndim)
print ("Is the Object empty 是否为空?")
print (s.empty)
print ("The size of the object 元素数据所占的字节数:")
print (s.size)

D:\Download\python3\python3.exe D:/Download/pycharmworkspace/s.py
s:
                   A         B         C         D
2017-01-01  0.007545  0.688495  0.973736  0.487351
2017-01-02 -0.196882  0.936148 -1.264392 -0.828813
2017-01-03  0.127409 -0.276271  0.837958 -0.559367
2017-01-04 -0.464785  0.800002  0.663286  0.455558
2017-01-05  1.030087  0.031511 -0.043613  0.004243
2017-01-06 -0.024684  0.656596  0.944321  1.237634
2017-01-07 -0.606596  0.464559 -0.071484  0.035291
2017-01-08  0.527749  0.409902  0.752180  1.407739
--------------------------------------------------
The axes are 数据的标签:
[DatetimeIndex([‘2017-01-01‘, ‘2017-01-02‘, ‘2017-01-03‘, ‘2017-01-04‘,
               ‘2017-01-05‘, ‘2017-01-06‘, ‘2017-01-07‘, ‘2017-01-08‘],
              dtype=‘datetime64[ns]‘, freq=‘D‘), Index([‘A‘, ‘B‘, ‘C‘, ‘D‘], dtype=‘object‘)]
The dimensions of the object 数据的维数:
2
Is the Object empty 是否为空?
False
The size of the object 元素数据所占的字节数:
32

Process finished with exit code 0