Find adverbs is not correct on the documentation

[RimChatti]

BPO	41259
Nosy	@rhettinger, @ezio-melotti, @Karnak123, @jacobtylerwalls
PRs	findAllAdverbs #21420 bpo-41259: fixed example for finding adverbs using re.findall() in docs #21728

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2022-02-05.09:22:41.071>
created_at = <Date 2020-07-09.16:42:02.800>
labels = ['expert-regex', 'easy', 'type-bug', '3.8', '3.9', '3.10']
title = 'Find adverbs is not correct on the documentation'
updated_at = <Date 2022-02-05.09:22:41.071>
user = 'https://bugs.python.org/RimChatti'

bugs.python.org fields:

activity = <Date 2022-02-05.09:22:41.071>
actor = 'serhiy.storchaka'
assignee = 'docs@python'
closed = True
closed_date = <Date 2022-02-05.09:22:41.071>
closer = 'serhiy.storchaka'
components = ['Regular Expressions']
creation = <Date 2020-07-09.16:42:02.800>
creator = 'Rim Chatti'
dependencies = []
files = []
hgrepos = []
issue_num = 41259
keywords = ['patch', 'easy']
message_count = 7.0
messages = ['373406', '373412', '373422', '373426', '373493', '374795', '412560']
nosy_count = 8.0
nosy_names = ['rhettinger', 'peter.otten', 'ezio.melotti', 'mrabarnett', 'docs@python', 'Rim Chatti', 'Sagnik Mazumder', 'jacobtylerwalls']
pr_nums = ['21420', '21728']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue41259'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']

[RimChatti]

re.findall(r"\w+ly", text) does not find all adverbs in a sentence, it finds words that contain ly (not ending with ly) :
if text= 'andlying clearly', output: [andly, clearly]
which is wrong!
the right way to do this is re.findall(r'\b(\w+ly)\b',text)
output= clearly!

[rhettinger]

Please submit a PR.

The parenthesis are not needed:
re.findall(r"\b\w+ly\b", text)

[RimChatti]

re.findall(r"\w+ly", text) does not find all adverbs in a sentence, it finds words that contain ly (not ending with ly) :
if text= 'andlying clearly', output: [andly, clearly]
which is wrong!
the right way to do this is re.findall(r'\b\w+ly\b',text)
output= clearly!

[peterotten]

While I don't want to start a philosical discussion -- is that really better? Finding adverbs with a regex doesn't work in the general case -- think butterfly, panoply, well -- and the example is meant to illustrate the usage of re.findall() rather than regex syntax.

"finding adverbs" is just shorter and easier to understand than "finding sequences of word characters that end with "ly".

[rhettinger]

I think it's fine as-is. The real purpose of the example is show basic patterns in writing regexes. Pig-latin examples or searching for words ending in -ly make for nice beginner examples. I like the OP's modification because it teaches a general skill (the importance of \b for making sure you get whole words).

We could add a link to the Natural Language Toolkit for people who are getting serious about searching for parts of speech.