I am working on a script in which one task is to "squash" strings of certain non-alphanumeric characters (however rare it might be to find two or more of them in a row). Well,<KBD> tr/// </KBD>to the rescue. I first used:

<KBD>tr/,()@+~#$%^&*-{}[]<>\/\|//s;</KBD>

It worked, sort of. But it would change a string such as<KBD> Mississippi </KBD>into<KBD> Misisipi</KBD>.

??? Then it occurred to me that perhaps the presence of the hyphen within the search-list might be making Perl "think" I'd asked for a range. This seemed pretty far-fetched, but I decided I should check the result of escaping the hyphen:

<KBD>tr/,()@+~#$%^&*\-{}[]<>\/\|//s;</KBD>

To my surprise, it worked; punctuation marks were "squashed" as I'd wanted. Repeated alphanumeric characters were left untouched. Moving the hyphen to the very end of the search-list also stopped the unwanted removal of alphanumeric characters.

Why did the hyphen as first used have that effect, when no range resembling<KBD> A-Z </KBD>or<KBD> a-z </KBD>seems to have specified?

As ever, thanks in advance . . .

In reply to Question concerning tr// by greenhorn

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