How can I manage units in pandas data?

I’m trying to figure out if there is a good way to manage units in my pandas data. For example, I have a DataFrame that looks like this:

   length (m)  width (m)  thickness (cm)
0         1.2        3.4             5.6
1         7.8        9.0             1.2
2         3.4        5.6             7.8

Currently, the measurement units are encoded in column names. Downsides include:

1. column selection is awkward — df['width (m)'] vs. df['width']
2. things will likely break if the units of my source data change

If I wanted to strip the units out of the column names, is there somewhere else that the information could be stored?

Answer

There isn’t any great way to do this right now, see github issue here for some discussion.

As a quick hack, could do something like this, maintaining a separate dict with the units.

In [3]: units = {}

In [5]: newcols = []
   ...: for col in df:
   ...:     name, unit = col.split(' ')
   ...:     units[name] = unit
   ...:     newcols.append(name)

In [6]: df.columns = newcols

In [7]: df
Out[7]:
   length  width  thickness
0     1.2    3.4        5.6
1     7.8    9.0        1.2
2     3.4    5.6        7.8

In [8]: units['length']
Out[8]: '(m)'