大熊貓：繞過數字索引

Question

有時候，我處理DataFrame S作數字索引，但我想繞過它根據自己的才能引用行，

In [49]: df = pandas.DataFrame(np.random.randn(3, 5)) 

In [50]: df 
Out[50]: 
      0   1   2   3   4 
0 -2.426211 0.670384 0.545880 -1.435168 0.675598 
1 0.507128 0.478832 -0.159536 -0.696284 -1.112171 
2 0.938019 -1.673491 -0.567462 0.381804 -1.280602 

In [51]: df[1:2] 
Out[51]: 
      0   1   2   3   4 
1 0.507128 0.478832 -0.159536 -0.696284 -1.112171 

In [52]: df2 = df.ix[1:2] 

In [53]: df2 
Out[53]: 
      0   1   2   3   4 
1 0.507128 0.478832 -0.159536 -0.696284 -1.112171 
2 0.938019 -1.673491 -0.567462 0.381804 -1.280602 

In [55]: df2.ix[0] 
--------------------------------------------------------------------------- 
KeyError         Traceback (most recent call last) 
... 

In [56]: df2.rename(index={1: "one", 2:"two"}) 
Out[56]: 
      0   1   2   3   4 
one 0.507128 0.478832 -0.159536 -0.696284 -1.112171 
two 0.938019 -1.673491 -0.567462 0.381804 -1.280602 

In [57]: df3 = df2.rename(index={1: "one", 2:"two"}) 

In [58]: df3.ix[0] 
Out[58]: 
0 0.507128 
1 0.478832 
2 -0.159536 
3 -0.696284 
4 -1.112171 
Name: one 

我怎樣才能繞過熊貓人指數訪問基礎矩陣索引？

Answer 1

您可以使用DataFrame.irow：

In [18]: df2 
Out[18]: 
      0   1   2 
1 2.279885 -0.414938 -2.230296 
2 -0.237980 -0.219556 1.231576 

In [19]: df2.irow(0) 
Out[19]: 
0 2.279885 
1 -0.414938 
2 -2.230296 
Name: 1 

In [20]: df2.irow([0, 1]) 
Out[20]: 
      0   1   2 
1 2.279885 -0.414938 -2.230296 
2 -0.237980 -0.219556 1.231576