AttributeError: 'numpy.ndarray' object has no attribute '_get_repr' with np.abs on a DatetimeIndex
I am trying to find the row of a DataFrame that is closest to a certain datetime. I have my data in a DataFrame which has a DatetimeIndex, and I can't use functions like `asof` because I need to get the closest row (either before _or_ after the time), so I am trying to implement the standard way of doing this which is getting the absolute difference between each index time and the time I want to find, then finding the row with the minimum difference.

However, there seems to be a strange bug with using np.abs with the pandas index, and it seems to be in the printing of the results stage (relating to `__get_repr`). Pandas prints things differently depending on how many rows the DataFrame has, and I think this is related here - as running the code on a 200 row DataFrame fails, but on a 100 row DataFrame it works! I've checked that its not some strange value in the DataFrame which is causing the problem, as a 100 row segment from anywhere in my original input file works, whereas a 200 row segment from anywhere fails.

Two input files (aeronet_large.txt with 200 rows and aeronet.txt with 100 rows) and the code I've been using are available at this gist: https://gist.github.com/robintw/631b53fa0cd9dbdabb36, and I asked a StackOverflow question about this (http://stackoverflow.com/questions/15115547/find-closest-row-of-dataframe-to-given-time-in-pandas) where I was recommended to raise an issue.
