Re^2: How to use a variable in tr///

As merlyn points out, that's not delimiter safe. However, it can be made safe with quotemeta:

eval sprintf "tr/%s/%s/", map quotemeta, $oldlist, $newlist;
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Update: of course nobull's construction below is much clearer. It should have occurred to me to say

eval "tr/\Q$oldlist\E/\Q$newlist\E/";
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Caution: Contents may have been coded under pressure.

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Re^3: How to use a variable in tr/// by dmorelli (Scribe) on Apr 08, 2005 at 14:52 UTC
This is great, but I was confused for a while and tinkered with it. Here's an annotated version: #! /usr/bin/perl -w use strict; my $fname = "aaabbbcccddd"; # Some creepy / characters to prove the quotemeta is doing its job my $orig = "abc/"; my $repl = "def/"; print "before: $fname\n"; $_ = $fname; eval sprintf "tr/%s/%s/", map quotemeta, $orig, $repl; $fname = $_; print "after: $fname\n"; =for explain The eval line above was confusing to me at first (and I'm not even a total newbie). It may help to see it delimited with more parenthesis: eval (sprintf ("tr/%s/%s/", map (quotemeta, $orig, $repl))); From right to left: The map uses quotemeta as its EXPR and $orig, $repl as its input list quotemeta is operating on a local $_ The two variables sprintf is expecting are in the list output from map eval is evaluating the resulting string made by sprintf. The tr/// is operating on $_ =cut [download]	[reply] [d/l]
Re^3: How to use a variable in tr/// by nobull (Friar) on Apr 08, 2005 at 16:37 UTC
I think I'd probably want to precompile too if this was to be used repeatedly. `my $tr = eval "sub { tr/\Q$oldlist\E/\Q$newlist\E/ }" or die $@; &$tr for $things, $that, $i, $want, $to, $transliterate;` [download]	[reply] [d/l]