pycases

pycases

A case conversion library for Python.

Features

• Automatic case detection, no need to specify the input case
• Extremely fast, written in Rust ✨
• Support for Unicode characters
• Support for providing acronyms in title case

Supported cases

Function	Output
cases.to_camel(s)	camelCase
cases.to_pascal(s)	PascalCase
cases.to_snake(s)	snake_case
cases.to_screaming_snake(s)	SCREAMING_SNAKE_CASE
cases.to_kebab(s)	kebab-case
cases.to_screaming_kebab(s)	SCREAMING-KEBAB-CASE
cases.to_train(s)	Train-Case
cases.to_lower(s)	lower case
cases.to_title(s)	Title Case
cases.to_upper(s)	UPPER CASE

Getting started

Install using

pip install pycases

Now convert a string using the relevant function.

import cases

cases.to_snake("XMLHttpRequest") # returns "xml_http_request"

Details

Each of the provided functions using the same underlying implementation which does the following:

• Divide the input string into words
• Convert each word as required
• Join the words back together optionally with a separator

Word boundaries are defined as follows:

• A set of consecutive Unicode non-letter and non-number characters.

  For example: 'foo _bar' is two words (foo and bar)

• A transition from a lowercase letter to an uppercase letter.

  For example: fooBar is two words (foo and Bar)

• A transition from multiple uppercase letters to a single uppercase letter followed by lowercase letters.

  For example: FOOBar is two words (FOO and Bar)

Functions where the transform is "title" accept an optional acronyms argument, which is a mapping of lowercase words to their output. For example:

>>> cases.to_pascal("xml_http_request", acronyms={"xml": "XML"})
'XMLHttpRequest'
>>> cases.to_pascal("xml_http_request", acronyms={"xml": "XML", "http": "HTTP"})
'XMLHTTPRequest'

Benchmarks

A simple benchmark against various other libraries is provided in ./benches. The following table shows the results when run on my Macbook M2 Max.

Library	Min (µs)	Max (µs)	Mean (µs)
cases	21.3750	49.6670	22.1288
pure python	62.8750	186.9580	66.2344
regex	80.8330	201.2500	87.0549
stringcase	101.8340	204.9590	108.6977
inflection	230.2920	581.4580	253.9194
case-conversion	1,431.7920	1,745.7080	1,506.2268

License

This project is licensed under the terms of the MIT license. See LICENSE for more details.