"Maybe you had a specific string in mind, but I don't see how this relates to the OP. He would not use Chi_2 in the regex pattern.

I did have a very similar string in mind.    

In a world where an identifier matches /^\w+\z/, you might do something like"
   ($_ = '\\Chi_2+3') =~ s/\\Chi\b/$chi/g; # Won't replace

I understand my update isn't contributing to the OP's original question. I'm not trying to distract from his post or the thread, simply attempting to correct what I said regarding the underscore having no effect on the RegEx's success (again the one I had in mind).

In my original reply I was referring to matching 'Chi' within 'Chi_2' using \b. I previously said that I didn't think the underscore would be a problem. However after some help in the CB from erix and Tanktalus it was shown that an underscore would interfere with this particular match:

 say (("Chi_2" =~ /\bChi\b/) ? "match" : "no match");
 returns: "no match"

  * Thanks again to Tantalus for this control structure.

Again, apologies for any confusion caused.


"...the adversities born of well-placed thoughts should be considered mercies rather than misfortunes." — Don Quixote

In reply to Re^3: Defining Characters in Word Boundary? by luis.roca
in thread Defining Characters in Word Boundary? by iaw4

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