in reply to Re^5: Regex match at the beginning or end of string
in thread Regex match at the beginning or end of string

That is only one of the constraints specified, which can be verified using @+ & @- after the match.
*After* the match? How? Consider the patterns /\w and \d, against the strings &8 and A8. After both 
"&8" =~ /^(?=.*(\w))(?=.*(\d))/;

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and 
"A8" =~ /^(?=.*(\w))(?=.*(\d))/;

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@- will be (0, 1, 1) and @+ will be (0, 2, 2), yet one of them fits the criteria from the OP, and the other doesn't.

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Re^7: Regex match at the beginning or end of string
by BrowserUk (Patriarch) on Feb 20, 2011 at 12:58 UTC

    Like I said, bad choices don't make good examples \w also matches '8'.

    Correct that and it is easy to see how to determine if the matches were consecutive from @- * @+ 

    "&8" =~ /^(?=.*([A-Z]))(?=.*(\d))/ and print "[@-][@+]";;

"A8" =~ /^(?=.*([A-Z]))(?=.*(\d))/ and print "[@-][@+]";;
[0 0 1][0 1 2]

"A+8" =~ /^(?=.*([A-Z]))(?=.*(\d))/ and print "[@-][@+]";;
[0 0 2][0 1 3]

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    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
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      Well, duh. If the patterns cannot overlap, it's easy and your suggestion, or my splitting into different regexes work fine. No checking of @- and @+ is needed.

      Of course I know \w matches 8. That was the point of the example. Both /^(?=.*\w)(?=.*\d)/ and /\w/ && /\d/ break down on this.

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        Of course I know \w matches 8. That was the point of the example.

        Then I'm sorry, but I still don't understand the point you are making?

        Using one regex that matches both required components, to check if the string contains both components just doesn't make any sense. To me at least.

        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
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