Individual Share Space

Pandas学习笔记03

31 Dec 2017 | free time

pandas学习笔记03

pandas.panel结构

pandas.Panel(data,items,major_axis,minor_axis,dtype,copy)

1. 创建Panel

  • 从ndarrays创建
  • 从DataFrames字典创建
从3维ndarray创建
# creating an empty panel\
import pandas as pd
import numpy as np

data = np.random.rand(2,4,5)
p = pd.Panel(data)
print p

<class 'pandas.core.panel.Panel'>
Dimensions: 2 (items) x 4 (major_axis) x 5 (minor_axis)
Items axis: 0 to 1
Major_axis axis: 0 to 3
Minor_axis axis: 0 to 4
从DataFrame对象字典创建
# creating an empty panel
import pandas as pd
import numpy as np
data = {'Item1':pd.DataFrame(np.random.randn(4,3)),
       'Item2':pd.DataFrame(np.random.randn(4,2))}
p = pd.Panel(data)
print p

<class 'pandas.core.panel.Panel'>
Dimensions: 2 (items) x 4 (major_axis) x 3 (minor_axis)
Items axis: Item1 to Item2
Major_axis axis: 0 to 3
Minor_axis axis: 0 to 2

创建一个空Panel

# creating an empty panel
import pandas as pd
p = pd.Panel()
print p

<class 'pandas.core.panel.Panel'>
Dimensions: 0 (items) x 0 (major_axis) x 0 (minor_axis)
Items axis: None
Major_axis axis: None
Minor_axis axis: None

2. 从Panel选择数据

从panel选择数据使用：

  • Items
  • Major_axis
  • Minor_axis
使用Items
# creating an empty panel
import pandas as pd
import numpy as np
data = {'Item1':pd.DataFrame(np.random.randn(4,3)),
       'Item2':pd.DataFrame(np.random.randn(4,2))}
p = pd.Panel(data)
print p['Item1']

          0         1         2
0  0.722992 -1.067307 -0.067804
1 -0.663662  0.772226  0.082438
2 -0.426947 -0.036010 -0.494841
3  2.124745 -0.172040  1.030734
使用major_axis, minor_axis
import pandas as pd
import numpy as np
data = {'Item1' : pd.DataFrame(np.random.randn(4, 3)),
        'Item2' : pd.DataFrame(np.random.randn(4, 2))}
p = pd.Panel(data)
print p['Item1'],'\n',p['Item2'],'\n'
print p.major_xs(1),'\n' # 1 indicated row index
print p.minor_xs(2) # 2 indicated col index

          0         1         2
0  0.267236  0.511752 -0.976870
1  0.068260  0.586807  0.268806
2  1.154739  1.528244  1.124225
3 -0.173479  0.281171 -1.515341
          0         1   2
0  0.092332 -0.592215 NaN
1 -2.058858 -0.896308 NaN
2 -0.586212  0.389448 NaN
3  2.188792  1.663543 NaN

      Item1     Item2
0  0.068260 -2.058858
1  0.586807 -0.896308
2  0.268806       NaN

      Item1  Item2
0 -0.976870    NaN
1  0.268806    NaN
2  1.124225    NaN
3 -1.515341    NaN

Related Posts

Comments