How i can extract substring from string using regular expression in .NET

Question

I want to extract sub string from string using regular expression ie. the following input/out list shows what i really want. i need to extract the dept filter conditions from a string. Here the word [dept] is constant.so what the kind of regular expression is useful to extract the sub string in this scenario

    Input------------------------------------------------Output 

    Some conditions And [dept]=IT                        [dept]=IT
    Some conditions And [dept]=IT Or [dept]=Account      [dept]=IT Or [dept]=Account
    Some conditions And [dept] IN ('IT','Account')       [dept] IN ('IT','Account')

    [dept]=IT And some conditions                        [dept]=IT
    [dept]=IT Or [dept]=Account And some conditions      [dept]=IT Or [dept]=Account 
    [dept] IN ('IT','Account') And some conditions       [dept] IN ('IT','Account')

Answer 1

This might be close to what you are after

(\[dept\]=\w+)( (Or)|(And))?|(\[dept\] IN \(.+?\))

It matches on your sample input like below, grouped in ().

([dept]=IT) 
([dept]=IT Or) ([dept]=Account) 
([dept] IN ('IT','Account'))

In your script you can join the groups on each line, ie., join ([dept]=IT Or) ([dept]=Account)

But if like suggested in the comments you are indeed parsing SQL, there are SQL parsers that will give you accurate access to your query WHERE expression.

Answer 2

\[dept\].*(?=\s+\bAnd\b)|\[dept\].*(?=$)

Try this.See demo.

http://regex101.com/r/dZ1vT6/41