Python Pandas Data Formatting
Question: I am in some sort of Python Pandas datetime purgatory and cannot seem to
figure out why the below throws an error. I have a simple date, a clear format
string, and a thus far unexplained ValueError. I've done quite a bit of
searching, and can't seem to get to the bottom of this.

On top of the issue below, what is the concept surrounding the format string
referred to as? In other words, where can I learn more about how the %m, %d,
and %Y can be changed and reconfigured to specify different formats?

Thanking you in advance from purgatory.

    
    
    In [19]: import pandas as pd
    
    In [20]: date = '05-01-11'
    
    In [21]: print type(date)
    <type 'str'>
    
    In [22]: pd.to_datetime(date, format = '%m-%d-%Y')
    ---------------------------------------------------------------------------
    ValueError                                Traceback (most recent call last)
    <ipython-input-22-24aff1dbfb25> in <module>()
    ----> 1 pd.to_datetime(date, format = '%m-%d-%Y')
    
    /Users/amormachine/anaconda/lib/python2.7/site-packages/pandas/tseries/tools.pyc in to_datetime(arg, errors, dayfirst, utc, box, format, coerce, unit, infer_datetime_format)
        323         return _convert_listlike(arg, box, format)
        324 
    --> 325     return _convert_listlike(np.array([ arg ]), box, format)[0]
        326 
        327 class DateParseError(ValueError):
    
    /Users/amormachine/anaconda/lib/python2.7/site-packages/pandas/tseries/tools.pyc in _convert_listlike(arg, box, format)
        311                 return DatetimeIndex._simple_new(values, None, tz=tz)
        312             except (ValueError, TypeError):
    --> 313                 raise e
        314 
        315     if arg is None:
    
    ValueError: time data '05-01-11' does not match format '%m-%d-%Y'  --> THE HELL IT DOESN'T!
    


Answer: `%Y` is a [four-digit year](https://docs.python.org/2/library/datetime.html).
You should find that `%y` will work.

