Regex required group of optional elements

Asked Jul 19 '17 at 13:16

Active Jul 19 '17 at 13:32

Viewed 28 times

I need to capture a 2 groups that are required, the thing is that the 2nd group is all ordered optional elements

so I thought I would do it like this

(a)(b?c?d?)

Problem is sometimes it only captures "a" only (it assumes group 2 is already there because its all optional :S)

anyway here is what I want to capture

ab
ac
ad
abcd

And here is not what I want to capture

a
b
bc
bcd
d
acbd

edited Jul 19 '17 at 13:32

asked Jul 19 '17 at 13:16

The Trice

Explain why `abcd` should match but `bc` should not match. Your logic is not clear to me. – Tim Biegeleisen Jul 19 '17 at 13:20
@TimBiegeleisen because a is required – The Trice Jul 19 '17 at 13:21
Your regex [already appears to be working](https://regex101.com/r/ImIyXg/2), is there an actual question here? – Tim Biegeleisen Jul 19 '17 at 13:24
its capturing a alone – The Trice Jul 19 '17 at 13:24
No it's not, check the demo. – Tim Biegeleisen Jul 19 '17 at 13:25
Isn't the OP asking how to just stop the regex matching "a" on its own? – Jimbo Jul 19 '17 at 13:27
@Jimbo Yes thank you!, I dont know why it was marked duplicate ! :S – The Trice Jul 19 '17 at 13:28
Shouldn't moderators marking questions as duplicate at least read the question !? – The Trice Jul 19 '17 at 13:30
1

@Wiktor don't you think https://stackoverflow.com/questions/2803221/regex-with-all-optional-parts-but-at-least-one-required (or something similar) would be a way better dupe? I don't see how the current dupe's answer the question at hand. – Sebastian Proske Jul 19 '17 at 13:31
@SebastianProske: Great find, I re-set the dupe reason. Still, the point is to match these patterns with anchors/word boundaries. – Wiktor Stribiżew Jul 19 '17 at 13:33
@SebastianProske Thanks thats what i was looking for ! – The Trice Jul 19 '17 at 13:34
@WiktorStribiżew word boundry doesn't do the trick – The Trice Jul 19 '17 at 13:37
@TheTrice Maybe not alone, but you still need them. https://regex101.com/r/qd1iep/1/ – Wiktor Stribiżew Jul 19 '17 at 13:38

Regex required group of optional elements

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