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Re: difference between ($scalar) and $scalar

by tachyon (Chancellor)
on Jul 21, 2001 at 13:19 UTC ( #98644=note: print w/replies, xml ) Need Help??

in reply to difference between ($scalar) and $scalar

To understand Perl you need to understand the notion of list versus scalar context. Many Perl functions can be called in either list or scalar context. What they return depends on the context in which tey were called. In scalar context they return a scalar value (often 1 for true if they succeed) whereas in list context they return a list of values. The examples below illustrate list versus scalar context as they apply to your question.

$str = "aa bb cc"; # scalar context $a = $str =~ m/(\w+)/; print "$a\n"; # prints 1 # list context (1 element list $a) ($a) = $str =~ m/(\w+)/g; print "$a\n"; # prints aa # list context (multi element array list) @a = $str =~ m/(\w+)/g; print "@a\n"; # prints aa bb cc

Another classic list versus scalar context gotcha is the localtime function which can either return a string that reads like Sat Jul 21 19:11:12 2001 in scalar context or a list. Run this code to see. Print applies a default list context.

print localtime(), "\n"; print scalar localtime(), "\n"; $time = localtime(); @time = localtime(); print "\$time => $time\n"; print "\@time => @time\n";

Hope this helps.




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