Renaming columns in a Pandas dataframe with duplicate column names?

Question

I have a df X with columns with duplicate names:

In [77]: X_R
Out[77]: 
      dollars  dollars
   0   0.7085   0.5000

I want to rename it

Answer 1

Here is another dynamic solution that I think is nicer

In [59]: df
Out[59]:
   a  x  x  x  z
0  6  2  7  7  8
1  6  6  3  1  1
2  6  6  7  5  6
3  8  3  6  1  8
4  5  7  5  3  0
In [61]: class renamer():
             def __init__(self):
                  self.d = dict()

              def __call__(self, x):
                  if x not in self.d:
                      self.d[x] = 0
                      return x
                  else:
                      self.d[x] += 1
                      return "%s_%d" % (x, self.d[x])

          df.rename(columns=renamer())
Out[61]:
   a  x  x_1  x_2  z
0  6   2   7   7  8
1  6   6   3   1  1
2  6   6   7   5  6
3  8   3   6   1  8
4  5   7   5   3  0