Regular expression to get substring from a string

Question

consider I have a string as following,

\n this is a paragraph. please ignore  \n this is a only for testing. please ignore \n

I have a search word as "only for testing". and I want to get the sentence which contains "only for testing" with in the \n the search word resides. In this case the output will be this is a only for testing. please ignore.

If I give paragraph as search word I should get the output as

this is a paragraph. please ignore

I have tried

test_str = "\\n this is a paragraph. please ignore  \\n this is a only for testing. please ignore \\n"
pattern = re.compile("\\\\n(.+?)\\\\n")
match = pattern.findall(test_str)

But not working as expected

print ([sent for sent in test_str.split("\\n") if 'only for testing' in sent]) (demo) — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Dec 12, 2019 at 12:57
If you're insisting on a Regex solution then you need to escape your search term for use in regex and then interpolate that string within (.+?) — MonkeyZeus
– MonkeyZeus, Commented Dec 12, 2019 at 13:00
You should Google the steps I mentioned individually. Here's a start, stackoverflow.com/q/280435/2191572. Are you new to Python too? — MonkeyZeus
– MonkeyZeus, Commented Dec 12, 2019 at 13:05
With regex, it will be a pain, see re.findall(r'(?:^|\\n)((?:(?!\\n).)*only for testing(?:(?!\\n).)*)', test_str) demo — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Dec 12, 2019 at 13:16

Wiktor Stribiżew · Accepted Answer · 2019-12-17 12:54:56Z

2

You may use a solution without a regular expression:

result = [sent for sent in test_str.split("\\n") if 'only for testing' in sent]

See the Python demo

Details

test_str.split("\\n") - split the text by \n
if 'only for testing' in sent - only keep the items that contain only for testing (for a case insensitive comparison, use if 'only for testing' in sent.lower())

answered Dec 17, 2019 at 12:54

Wiktor Stribiżew

631k41 gold badges502 silver badges633 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Regular expression to get substring from a string

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related