lo'c iloc at iat ix举例

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loc: only work on index iloc: work on position ix: You can get data from dataframe without it being in the index at: get scalar values. It's a very fast loc iat: Get scalar values. It's a very fast iloc

1   If at and iat are very fast versions of loc and iloc, then why use loc and iloc at all? – RaySep 28 '16 at 9:51 7   atand iat a meant to access a scalar, that is, a single element in the dataframe, while loc and ilocare ments to access several elements at the same time, potentially to perform vectorized operations.– ncasas Oct 7 '16 at 9:24 add a comment 具体例子 df = pd.DataFrame({'A':['a', 'b', 'c'], 'B':[54, 67, 89]}, index=[100, 200, 300]) df A B 100 a 54 200 b 67 300 c 89 In [19]: df.loc[100] Out[19]: A a B 54 Name: 100, dtype: object In [20]: df.iloc[0] Out[20]: A a B 54 Name: 100, dtype: object In [24]: df2 = df.set_index([df.index,'A']) df2 Out[24]: B A 100 a 54 200 b 67 300 c 89 In [25]: df2.ix[100, 'a'] Out[25]: B 54 Name: (100, a), dtype: int64