non-reversible case conversion

[Eraldo]

• What is the current behavior?

>>> from graphene.utils.str_converters import to_snake_case
>>> from graphene.utils.str_converters import to_camel_case

>>> to_camel_case("my_variable_1")
'myVariable1'

>>> to_snake_case("myVariable1")
'my_variable1'

• What is the expected behavior?

>>> from graphene.utils.str_converters import to_snake_case
>>> from graphene.utils.str_converters import to_camel_case

>>> to_camel_case("my_variable_1")
'myVariable1'

>>> to_snake_case("myVariable1")
'my_variable_1'

• What is the motivation / use case for changing the behavior?

Being able to convert objects/properties back and forth between server and client.
Also useful for introspecting and debugging use cases.

In my particular case, I receive an object on my server that the client got from the api and I want to associate it with the source which I now need an extra mapping for since the conversion is one-directional.

• Please tell us about your environment:

Version: graphene-django 2.10.0

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. stackoverflow)

This is where in graphene it is happening: #1204

My current workaround is to add an underscore in case of trailing numbers:

input = re.sub(r'(.*)(\d+)$', r'\1_\2', input) 

I have 2 solution suggestions:

1. Adding an underscore in case of trailing numbers.
2. Not removing the underscore in case of trailing numbers (like _1).

[abhushansahu]

For your use-case, I believe this can also work.

re.sub("([a-z]+)(([A-Z][0-9])*)", r"\1_\2", name)

[Eraldo]

For your use-case, I believe this can also work.

re.sub("([a-z]+)(([A-Z][0-9])*)", r"\1_\2", name)

Thanks @abhushansahu for the comment.

This adds an underscore before each digit.
E.g.:

In [6]: re.sub(r'(.*)(\d+)$', r"\1_\2", "http2Module1").lower()                 
Out[6]: 'http2module_1'

In [7]: re.sub("([a-z]+)(([A-Z][0-9])*)", r"\1_\2", "http2Module1").lower()     
Out[7]: 'http_2module_1'