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From: PerlFAQ Server on 12 Jun 2010 18:00
This is an excerpt from the latest version perlfaq4.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .

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4.37: What's wrong with always quoting "$vars"?

The problem is that those double-quotes force stringification--coercing
numbers and references into strings--even when you don't want them to be
strings. Think of it this way: double-quote expansion is used to produce
new strings. If you already have a string, why do you need more?

If you get used to writing odd things like these:

print "$var"; # BAD
$new = "$old"; # BAD
somefunc("$var"); # BAD

You'll be in trouble. Those should (in 99.8% of the cases) be the
simpler and more direct:

print $var;
$new = $old;
somefunc($var);

Otherwise, besides slowing you down, you're going to break code when the
thing in the scalar is actually neither a string nor a number, but a
reference:

func(\@array);
sub func {
my $aref = shift;
my $oref = "$aref"; # WRONG
}

You can also get into subtle problems on those few operations in Perl
that actually do care about the difference between a string and a
number, such as the magical "++" autoincrement operator or the syscall()
function.

Stringification also destroys arrays.

@lines = `command`;
print "@lines"; # WRONG - extra blanks
print @lines; # right



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are not necessarily experts in every domain where Perl might show up,
so please include as much information as possible and relevant in any
corrections. The perlfaq-workers also don't have access to every
operating system or platform, so please include relevant details for
corrections to examples that do not work on particular platforms.
Working code is greatly appreciated.

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