Re^3: How to use a variable in tr///

why not just eval?

Because with eval, you must worry about delimiters. For example, if either string had contained "/", the eval example given elsewhere in this thread would fail. Also, eval invites disaster in a proxy-privilege environment (like CGI or other daemons).

The lookup table isn't hard to create:

## initialization
my $old = 'abc';
my $new = 'xyz';
my %table; @table{split //, $old} = split //, $new;
my $table_re = join '|', map quotemeta reverse sort keys %table;

## the deed
my $string = 'abracadabra';
$string =~ s/($table_re)/$table{$1}/g;
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-- Randal L. Schwartz, Perl hacker
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Re^4: How to use a variable in tr/// by Roy Johnson (Monsignor) on Apr 08, 2005 at 12:49 UTC
The "why not just eval?" referred to the case of embedding an eval'd tr/// in an s///e, which would be no better. But your cautions are valid. [Update: and addressed here] Update: Though for character replacement, I'd build the regex using a character class rather than alternation: `my $table_re = sprintf '[%s]', join '', map quotemeta, keys %table;` [download] Caution: Contents may have been coded under pressure.	[reply] [d/l]

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Re^4: How to use a variable in tr///
by Roy Johnson (Monsignor) on Apr 08, 2005 at 12:49 UTC

here

Update:
Though for character replacement, I'd build the regex using a character class rather than alternation:

my $table_re = sprintf '[%s]', join '', map quotemeta, keys %table;
[download]

Caution: Contents may have been coded under pressure.

[reply]
[d/l]