How to include optional space between two words without picking next word?

Question

I have these below file names and using below regex to match:

File Names:

1234 12345678 TEST DOCUMENT December 20, 2018.pdf
1234 12345678 TESTDOCUMENT December 20, 2018.pdf

Regex I am using to match the file name is:

(\d+)\s(\d+)\s(\w+\s?\w+)

for the first file it is working, but for the 2nd file it is matching month December also as these are two words with a space too.

How to write a regex to match only upto "1234 12345678 TEST DOCUMENT" in both cases with or with out space between TEST and DOCUMENT.

Expected Result:

1234 12345678 TEST DOCUMENT
1234 12345678 TESTDOCUMENT

Not this for 2nd file(1234 12345678 TESTDOCUMENT December)

How are you expected to distinguish between those two cases? Will it always say "TEST DOCUMENT" or might it be some other name? — Robert Harvey, Dec 21 '18 at 15:54
It could be any text. Possible combination is two words with a space — Bhanuchandar Challa, Dec 21 '18 at 15:55
Then I don't see how you can tell the difference between the two. There aren't any distinguishing characteristics, unless you have something else like fixed columns. — Robert Harvey, Dec 21 '18 at 15:56
After TEST DOCUMENT, it is always a month in format January-December — Bhanuchandar Challa, Dec 21 '18 at 15:56
Ok. Then part of your regex needs to match on all twelve month names, something like [this](https://stackoverflow.com/questions/2655476/regex-to-match-month-name-followed-by-year). That will give you your ending demarcation. — Robert Harvey, Dec 21 '18 at 15:57

score 3 · Accepted Answer · answered Dec 21 '18 at 15:59

3

Given that you said

After TEST DOCUMENT, it is always a month in format January-December

You can use a lookahead to ensure that you don't match the month:

(\d+)\s(\d+)\s(\w+\s?(?!Jan|Feb|Mar|...|Dec)\w+)
                     ^^^^^^^^^^^^^^^^^^^^^^^...

This will ensure that the second word doesn't start with month names.

answered Dec 21 '18 at 15:59

iBug

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Thanks for the answer. It can be any no of words before the month, but not only the second word. Is there any way to match it? – Bhanuchandar Challa Jan 04 '19 at 20:40
This worked. (\d+)\s(\d+)\s(.+?(?=January|February|March|April|May|June|July|August|September|October|November|December)) – Bhanuchandar Challa Jan 04 '19 at 20:48

The fourth bird · Answer 2 · 2018-12-21T16:08:56.243

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Another option is to match the "datelike" format at the end and capture what is before in a capturing group:

(\d+)\s(\d+)\s(.*?)\s\d{1,2},\s\d{4}\.pdf$

Regex demo

As @iBug points out, if you only want to match word characters or a whitespace you could replace (.*?) with ([\w ]+)

edited Dec 21 '18 at 16:08

answered Dec 21 '18 at 16:02

The fourth bird

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`\w+` is better than `.*?`. – iBug Dec 21 '18 at 16:03
@iBug It depends on the content what is in between. In this case it could be `[\w ]+`. Added your suggestion to my answer. – The fourth bird Dec 21 '18 at 16:06

score 1 · Answer 3 · answered Dec 21 '18 at 16:05

1

Just make sure to always match the part with the date, for example:

(\d+)\s(\d+)\s(\w+\s?\w+)\s\w+\s\d+

Would be enough.

answered Dec 21 '18 at 16:05

aleon

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score 0 · Answer 4 · answered Dec 21 '18 at 16:08

You can select everything from the start of the line that is followed by (the lookahead (?=...)) a white space and the name of a month. Here is for november and december:

^.*(?= December| November)

Be careful with the cases of the month names (camelcase, upper, etc). Also, do you have localized data, months names in different languages...

How to include optional space between two words without picking next word?

4 Answers4