Hash slice in regex

anjiro has asked for the wisdom of the Perl Monks concerning the following question:

Is there any way to force a hash slice to interpolate without spaces when used in a regex? I have a huge hash table like so:

my %k;
$k{'A'} = 'Foo';
$k{'B'} = 'Bar';
$k{'C'} = 'Baz';
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I want to replace all occurences of 'FooBarBaz' with something else, say "stuff". However, this doesn't work:

s/@k{qw(A B C)}/stuff/;
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because it interpolates to

s/Foo Bar Baz/stuff/;
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rather than

s/FooBarBaz/stuff;
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This is particularly irritating because

print @k{qw(A B C)}, $/;
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yields "FooBarBaz". Any thoughts? Yes, I could do

$x = join('', @k{qw(A B C)});
s/$x/stuff/;
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But that's so ugly...

Comment on Hash slice in regex Select or Download Code

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Re: Hash slice in regex by ikegami (Patriarch) on Sep 26, 2006 at 17:21 UTC
The equivalent `print` would have been `print "@k{qw(A B C)}";`. Remember that `m/.../` is a quote-like operator. The element seperator for interpolated slices and arrays is the value of `$"`. `#!perl -l my %k; $k{'A'} = 'Foo'; $k{'B'} = 'Bar'; $k{'C'} = 'Baz'; { # What goes for double-quotes... print "@k{qw(A B C)}"; # Foo Bar Baz local $" = ''; print "@k{qw(A B C)}"; # FooBarBaz } { # ...also goes for the regexp operators. print qr/@k{qw(A B C)}/; # Foo Bar Baz local $" = ''; print qr/@k{qw(A B C)}/; # FooBarBaz }` [download] Update: Added `qr/.../` to the example.	[reply] [d/l] [select]
Re^2: Hash slice in regex by anjiro (Beadle) on Sep 26, 2006 at 17:26 UTC
Ah-ha! I knew there would be something like that! Too many darn man pages to wade through... =)	[reply]
Re: Hash slice in regex by hgolden (Pilgrim) on Sep 26, 2006 at 17:26 UTC
Hey You want to change `$"`. According to Programming Perl: "When an array or slice is interpolated into a double-quoted string (or the like), this variable specifies the string to put between individual elements. Default is a space". Hays Update: Too much time looking for the right page in PP makes my post redundant, but enjoy the reading from the Good Book.	[reply] [d/l]