This is pretty thorough:
def convert(name):
s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()
Works with all these (and doesn't harm already-un-cameled versions):
>>> convert('CamelCase')
'camel_case'
>>> convert('CamelCamelCase')
'camel_camel_case'
>>> convert('Camel2Camel2Case')
'camel2_camel2_case'
>>> convert('getHTTPResponseCode')
'get_http_response_code'
>>> convert('get2HTTPResponseCode')
'get2_http_response_code'
>>> convert('HTTPResponseCode')
'http_response_code'
>>> convert('HTTPResponseCodeXYZ')
'http_response_code_xyz'
Or if you're going to call it a zillion times, you can pre-compile the regexes:
first_cap_re = re.compile('(.)([A-Z][a-z]+)')
all_cap_re = re.compile('([a-z0-9])([A-Z])')
def convert(name):
s1 = first_cap_re.sub(r'\1_\2', name)
return all_cap_re.sub(r'\1_\2', s1).lower()
Don't forget to import the regular expression module
import re
There's an inflection library in the package index that can handle these things for you. In this case, you'd be looking for inflection.underscore()
:
>>> inflection.underscore('CamelCase')
'camel_case'