How should I write this regular expression string.

I am doing a few regular expressions and I am having trouble combining all the alternatives here.

I have 3 different patterns I would like to combine.

Pattern 1:

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##### = Up to 5 digit serial number
AAA = 3-letter code can be (DEL|KOL|MUM|CHE)
YYYY = a year

My start on this is the following..
\b(IN)? ?(\d[, ]?){1,5}(\/(DEL|KOL|MUM|CHE)\/)\d{4}(\s?(B|[IP][1234]))?\b

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2nd Pattern:

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IN = the two characters "IN"
PCT = The three characters "PCT"
YYYY = Year
##### = Up to 5 digit serial number
AAA = 3-letter code can be (DEL|KOL|MUM|CHE)

3rd Pattern:

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##### = Up to 5 digit serial number
AAA = 3-letter code can be (DEL|KOL|MUM|CHE)
NP = the characters "NP"
YYYY is the year.

All formats end with
(B, I1, I2, I3, I4, P1, P2, P3, P4)

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thus you can see in my start on this

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which I am pretty sure covers it pretty well, but am always open to suggestions.
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What's the context for this? Do you know which regexp engine you have available?

For your sanity and anyone (including you) who has to look at this code a couple of months or years from now, is there any way you can accept multiple match attempts instead of rolling it all into one grand regexp?

Is it your expectation to capture parts of the match for use elsewhere in your code?

One of the things that might make this hard is distinguishing serial numbers with 4 digits from years, since in some formats the #### could precede the YYYY and in others it looks like the order could be the reverse.

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darbid73Author Commented:
Good questions JMCG. These formats are the possible formats of an Indian patent number.  I am currently trying to recognize patent numbers such as this.

Sanity is always important, but my main issue is I know very little about regular expressions and am worried that my end result is not very efficient.

I will be using a .NET engine.

I want it to find the whole number, the only thing that is optional is the kind code on the end.  So all these combinations are possible....

IN 56987/KOL/1999
IN56987/KOL/1999 I2
IN/PCT/2004/96545/KOL B
IN 54565/DELNP/2015

I have just noticed that my original question does not have "IN" at the beginning of all of them. I am going to make this a rule that "IN" must be at the beginning.
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darbid73Author Commented:
Under my small change that an IN is at the beginning and with the help of OZO I have this

IN ?(\d{1,5}\/(DEL|KOL|MUM|CHE)(NP)?\/\d{4})|(IN\/PCT\/\d{4}\/\d{1,5}\/(DEL|KOL|MUM|CHE))(\s?(B|[IP][1234]))?

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I would also suggest a tool like Expresso ( It helps with documentation of the RegEx and easy testing.View from Expresso
That's quite a nice tool! I note that you missed the space in front of the first question mark.

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Regular Expressions

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