New submission from Vajrasky Kok: According to:
http://oald8.oxfordlearnersdictionaries.com/dictionary/alphanumeric http://en.wikipedia.org/wiki/Alphanumeric Alphanumeric is defined as [A-Za-z0-9]. Underscore (_) is not one of them. One of the documentation in Python (Doc/tutorial/stdlib2.rst) differentiates them very clearly: "The format uses placeholder names formed by ``$`` with valid Python identifiers (alphanumeric characters and underscores). Surrounding the placeholder with braces allows it to be followed by more alphanumeric letters with no intervening spaces. Writing ``$$`` creates a single escaped ``$``::" Yet, in documentations as well as comments in regex, we implicitely assumes underscore belongs to alphanumeric. Explicit is better than implicit! Attached the patch to differentiate alphanumeric and underscore in documentations and comments in regex. This is important in case someone is confused with this code: >>> import re >>> re.split('\W', 'haha$hihi*huhu_hehe hoho') ['haha', 'hihi', 'huhu_hehe', 'hoho'] On the side note: In Python code base, sometimes we write "alphanumerics" and "underscores", yet sometimes we write "alphanumeric characters" and "underscore characters". Which one again is the true way? ---------- assignee: docs@python components: Documentation files: fix_alphanumeric_and_underscore_doc_in_regex.patch keywords: patch messages: 195611 nosy: akuchling, docs@python, vajrasky priority: normal severity: normal status: open title: Misleading documentations and comments in regular expression about alphanumerics and underscore versions: Python 3.3, Python 3.4 Added file: http://bugs.python.org/file31371/fix_alphanumeric_and_underscore_doc_in_regex.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue18779> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
