python学习记录

range(1,5)  <<<[0,1,2,3,4]  返回的是数

np.arrange(1,5) <<<([0,1,2,3,4)])是list

>>> a = np.arange(6).reshape((3, 2))
>>> a
array([[0, 1],
       [2, 3],
       [4, 5]])

reshape 前面是行数，后面是列数

data1
Out[33]: 
   a  b  c
0  0  1  2
1  3  4  5
data2
Out[34]: 
    a   y   z
0  20  21  22
1  23  24  25

data=pd.concat([data1,data2],axis=0)
data
Out[22]: 
    a    b    c     y     z
0   0  1.0  2.0   NaN   NaN
1   3  4.0  5.0   NaN   NaN
0  20  NaN  NaN  21.0  22.0
1  23  NaN  NaN  24.0  25.0
data=pd.concat([data1,data2],axis=1)
data
Out[24]: 
   a  b  c   a   y   z
0  0  1  2  20  21  22
1  3  4  5  23  24  25