Re: Strange compiler behavior with map?

The compiler has to decide whether "{" is the start of a block or the start of a hash constructor.

The standard way to disambiguate would be:

my %unique  = map {; "$_" => 1 } @objects;
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But this would work:

my %unique  = map { $_ => 1 } @objects;
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By the way, if you want to preserve the original order, you can use:

my %seen;
my @unique = grep !$seen{$_}++, @objects;
print @unique;
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Also, it won't convert your objects into strings.

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Re^2: Strange compiler behavior with map? by dwalin (Monk) on Sep 05, 2011 at 09:26 UTC
The purpose of this statement is to normalize objects and scalar values to their string representation, hence explicit "$_"; I wanted to make it stand out and catch the eye when I will need to return to that code. {; does the trick nicely, thanks. And many thanks for the second idiom, now that's a real nice solution. I think I've seen it before but somehow it didn't registered until now. I need to remember it the next time. Regards, Alex.	[reply]
Re^3: Strange compiler behavior with map? by Anonymous Monk on Sep 05, 2011 at 09:37 UTC
And many thanks for the second idiom, now that's a real nice solution. I think I've seen it before but somehow it didn't registered until now. I need to remember it the next time. The FAQ remembers the FAQ for you :) grep{!$seen{$_}++} site:perldoc.perl.org ► How can I remove duplicate elements from a list or array? FAQy FAQ is FAQ :D The other Anonymous monk	[reply]
Re^3: Strange compiler behavior with map? by ikegami (Patriarch) on Sep 06, 2011 at 00:51 UTC
Stringifying version: `my %seen; my @unique = grep !$seen{$_}++, map "$_", @objects;` [download] `my %seen; my @unique = map !$seen{$_}++ ? "$_" : (), @objects;` [download]	[reply] [d/l] [select]