python，pandas， DataFrame数据获取方式

1 1 df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],columns=[‘A‘, ‘B‘, ‘C‘])
2 2 >>> df
3 3     A   B   C
4 4 0   0   2   3
5 5 1   0   4   1
6 6 2  10  20  30

1 >>> df.at[4, ‘B‘]
2 2
3 >>> df.iloc[5].at[‘B‘]
4 4

1 >>> df.iat[1, 2]
2 1
3 >>> df.iloc[0].iat[1]
4 2

1 >>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],index=[‘cobra‘, ‘viper‘, ‘sidewinder‘],columns=[‘max_speed‘, ‘shield‘])
2 >>> df
3             max_speed  shield
4 cobra               1       2
5 viper               4       5
6 sidewinder          7       8

 1 1 >>> df.loc[‘cobra‘, ‘shield‘]
 2 2 2
 3 返回series:
 4 3 >>> df.loc[‘viper‘]
 5 4 max_speed    4
 6 5 shield       5
 7 6 Name: viper, dtype: int64
 8 返回dataframe：
 9 >>> df.loc[[‘viper‘, ‘sidewinder‘]]
10             max_speed  shield
11 viper               4       5
12 sidewinder          7       8

1 >>> df.iloc[0, 1]
2 2
3 返回series:
4 >>> df.iloc[0]
5 a    1
6 b    2
7 c    3
8 d    4
9 Name: 0, dtype: int64