Question

I have the following regexp

var value = "hello";
"(?<start>.*?\W*?)(?<term>" + Regex.Escape(value) + @")(?<end>\W.*?)"

I’m trying to figure out the meaning, because it doesnt work against the single word.
for example, it matches “they said hello us”, but fails for just “hello”

can you please help me to decode what does this regexp string mean?!

PS: it’s .NET regexp

Answer 1

Its because of \W in last part. \W is non A-Z0-9_ char.

In “they said hello us”, there is space after hello, but “hello” there is nothing there, thats why.

If you change it to (?<end>\W*.*?) it may work.

Actually, the regex itself does not make sense for me, it should rather like

"\b" + Regex.Escape(value) + "\b"

\b is word boundary