Problem using argsort in DataFrame
```
In [90]: df
Out[90]: 
          A         B         C         D         E
0  0.444939  0.407554  0.460148  0.465239  0.462691
1  0.016545  0.850445  0.817744  0.777962  0.757983
2  0.934829  0.831104  0.879891  0.926879  0.721535
3  0.117642  0.145906  0.199844  0.437564  0.100702

In [91]: df2 = df.apply(lambda row: df.columns[np.argsort(row)], axis=1)

In [92]: df2
Out[92]: 
```
#### Output

```
   A  B  C  D  E
0  B  A  C  E  D
1  A  E  D  C  B
2  E  B  C  D  A
3  E  A  B  C  D
```
#### Expected Output

```
   1  2  3  4  5
0  B  A  C  E  D
1  A  E  D  C  B
2  E  B  C  D  A
3  B  C  D  E  A
```

Last row of the dataframe has different values. But rest of the rows has same value as expected.

[http://stackoverflow.com/questions/39605512/twist-dataframe-by-rank/39610093#39610093](url)
