CamelCase Conversions

[snippsat]

There are some libraries for this eg stringcase, Inflection.

λ ptpython
>>> from stringcase import snakecase, camelcase, pascalcase

>>> snakecase('DeathToCamelCase')
'death_to_camel_case'
>>> camelcase('death_to_camel_case')
'deathToCamelCase'
>>> pascalcase('death_to_camel_case')
'DeathToCamelCase'

# Fail on this
>>> snakecase('getHTTPResponseCode')
'get_h_t_t_p_response_code'

This can also be good exercise to do in regex.
For many cases a would a expression like (?!^)([A-Z]+) work.

>>> import re
>>> 
>>> re.sub(r'(?!^)([A-Z]+)', r'_\1', 'DeathToCamelCase').lower() 
'death_to_camel_case'
>>> re.sub(r'(?!^)([A-Z]+)', r'_\1', 'FooBarBaz').lower() 
'foo_bar_baz'
>>> re.sub(r'(?!^)([A-Z]+)', r'_\1', 'getHTTPResponseCode').lower() 
'get_httpresponse_code'

Looking at net so have some made better like eg ((?<=[a-z0-9])[A-Z]|(?!^)[A-Z](?=[a-z])).