wesm/pandas — pull request #515 by bshanks (2011-12-21 07:58:45+00:00)
Title: optional keyword argument 'itemsize' for HDFStore.put and HDFStore.append to control string length; default 255

added optional keyword argument 'itemsize' to HDFStore.put and HDFStore.append

it sets the string length of strings in the index and columns for the table (rather than the previous behavior, which was to take the max string length from the longest index/column string in the dataset that is used to create the table). Default is 255.

even with this commit, strings such as column names which are longer than "itemsize" and which are .appended in the future will be silently truncated. I recommend that a warning be raised when this happens, but i didn't add that myself because i couldn't easily find the place where the truncation occurs, or how to extract the current string length.