Re: [NEWBIE] newline question

From: Randal L. Schwartz (merlyn_at_stonehenge.com)
Date: 03/31/04 

Date: 31 Mar 2004 13:52:28 -0800

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>>>>> "Gunnar" == Gunnar Hjalmarsson <noreply@gunnar.cc> writes:

Gunnar> That works, but it's clearer written as:

Gunnar> @lines = map { tr/\n//d; $_ } @lines;

I don't consider that clearer. The loop first modifies @lines (via
the side effect of having changed $_ in the map block), then gathers
all those results together to create a new list, then assigns the
entire new list over the top of the identically updated list.

Weird. Definitely not clearer, and more dangerous too. Consider
the obvious cut-and-paste mangling:

@newlines = map { tr/\n//d; $_ } @lines;

Your copy of @lines and @newlines are identical, even though you might
expect @lines to remain unaffected!

Definitely bad. Definitely don't do this. Not without the required
BIG HONKIN COMMENT to the right describing how wasteful you are.

print "Just another Perl hacker,"; # yeah, the guy who invented this phrase 

-- 
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
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