DataFrame的基本操作

DataFrame的基本操作

1，选择

(1),Select column

In [11]: df['a']
Out[11]:
0   -1.355263
1    0.010888
2    1.599583
3    0.004565
4    0.460270
Name: a, dtype: float64

(2),Select row by label

In [15]: df.loc[1]
Out[15]:
a    0.010888
b   -0.900427
c   -0.397198
Name: 1, dtype: float64

(3) Select row by integer location

In [19]: df.iloc[1]
Out[19]:
a    0.010888
b   -0.900427
c   -0.397198
Name: 1, dtype: float64

(4) Slice rows

In [24]: df[1:3]
Out[24]:
          a         b         c
1  0.010888 -0.900427 -0.397198
2  1.599583  0.662713  0.943103

(5) Select rows by boolean vector

In [27]: df[df['a']>0.5]
Out[27]:
          a         b         c
2  1.599583  0.662713  0.943103

2,删除

In [28]: del df['a']

In [29]: df
Out[29]:
          b         c
0  1.451534 -0.497793
1 -0.900427 -0.397198
2  0.662713  0.943103
3 -0.505622  1.156941
4  0.333584 -1.260798

In [32]: df.pop('b')
Out[32]:
0    1.451534
1   -0.900427
2    0.662713
3   -0.505622
4    0.333584
Name: b, dtype: float64

In [33]: df
Out[33]:
          c
0 -0.497793
1 -0.397198
2  0.943103
3  1.156941
4 -1.260798

3，插入

In [35]: df['e']=['e','w','t','e','d']

In [36]: df
Out[36]:
          c  e
0 -0.497793  e
1 -0.397198  w
2  0.943103  t
3  1.156941  e
4 -1.260798  d