convert database_column_names to mixedCaseNames and back again

by @jehiah on 2006-06-14 06:33UTC
Filed under: All , Python , Programming

It’s common to name your database columns like this_is_a_column with what I call “underscore case”. It’s also twice as common to name variables in your code with either CamelCaseFormat or mixedCaseFormat. I hate the tedious effort of going between the two, so here is a snippet of python that does the work for me.

It works by passing a column name to a transform function that processes it through a regular expression. That regular expression passes the matched groups through a helper function before putting it all back together again.

import re
def toMixedCase(columnName):
    """ pass 'a_column_name' get back 'aColumnName' """
    return re.sub("(_[a-zA-Z])",toMixedCaseHelper,columnName)
def toMixedCaseHelper(match):
    """ pass a match of '_a' and you get back 'A' """

def toUnderscoreCase(columnName):
    """ pass 'aColumnName' and get back 'a_column_name' """
    return re.sub("([a-z][A-Z])",toUnderscoreCaseHelper,columnName)
def toUnderscoreCaseHelper(match):
    """ pass a match of 'aZ' and get back 'a_z' """
    return[0] + '_'[1].lower()


Now let’s see it at work:

>>> import caseTransformations
>>> caseTransformations.toMixedCase("your_column_name")
>>> caseTransformations.toUnderscoreCase("yourMixedCaseName")


It might not be perfect, and you could speed it up by pre-compiling the regular expressions, but I’m happy with it (and open to suggestions of a better implementation)

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