in reply to regex issue

I would something like: 
foreach my $line (@filedata) {
    s{(\Qhttp://v3vi.click4assistance.co.uk/c4a.aspx?AccNo=Inter12109&
+amp;IDENT=\E)US/${1}UK/g;
}

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Re^2: regex issue
by ack (Deacon) on Dec 11, 2009 at 17:49 UTC

    Doesn't the regex substitution pattern have two parts...the part to be look for and the part to use for the replacement?

    I like your solution, but I'm confused by the use of braces (i.e., { and }) for the first part and then it appears you're using the slash, /, for the second part.

    Did you mean:

    s{(\Qhttp://v2vi.click4assistance.co.uk/c4a.aspx?AccNo=Inter12109&IDENT=\E)US}${1}US}/g

    If so, then how can you use the braces to separate the part of the substitution and also for the numeric placeholder? It seems like it should be something like this:

    s|(\Qhttp://v3vi.click4assistance.co.uk/c4a.aspx?AccNo=Inter12109&
+IDENT=\E)US|${1}UK|g;

    [download]

    so that the regex separators are distinct from the characters (like the braces) and don't get confused with the separators.

    But you're a lot more experienced than I, so I'm sure I'm missing something...something that's probably obvious. As I noted, I really like your regex...even though I don't entirely understand it...so I'm anxious to learn more.

    Thanks, JavaFan, I always learn from eveyone here.

    ack Albuquerque, NM
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      Yes, I should have used {} all the way: 
      s{(\Qhttp://v2vi.click4assistance.co.uk/c4a.aspx?AccNo=Inter12109&
+IDENT=\E)US}{${1}UK}g

      [download]
      Note that both the pattern and the replacement have their own set of parens. You may write: 
      s{(\Qhttp://v2vi.click4assistance.co.uk/c4a.aspx?AccNo=Inter12109&
+IDENT=\E)US}
 {${1}UK}g

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      as well.
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