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Actually, it is not a scoping issue. By that logic, this should also save memory:
sub get_size { my @a = big_list(); return scalar @a } my $size = get_size();

However, in a simple test, that uses the same memory as a global array that does the same thing.

Perl, generally speaking, does not release memory back to the OS unless your system is running out of memory. The memory from lexical variables can be claimed and reused by Perl, but it doesn't go back to the OS.

All of the other methods created an array in addition to what was copied on the stack. map only creates an array of 1s in addition to what was copied on the stack; thus it uses less memory (unless your original data is no bigger than integers, of course) (and yes, this was not always true in older versions of Perl).



When's the last time you used duct tape on a duct? --Larry Wall

In reply to Re^3: Trouble getting size of list returned from sub by ColonelPanic
in thread Trouble getting size of list returned from sub by wanna_code_perl

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    [marinersk]: Corion This DBA wants to smack others who like putting whitespace in column names.
    [marinersk]: s/smack/whap/;
    [talexb]: Wow, what hilariously bad form.
    [SuicideJunkie]: Just wait; someday soon, you'll be given a DB with unicode emojis in the column names.
    [Corion]: marinersk: Well, I have done select statements like select sum(foo) as "Total Amount", ..., but to have a table like that makes me shudder
    [Corion]: SuicideJunkie: :-D
    [marinersk]: SuicideJunkie LOL
    [choroba]: Woohoo! Fixed a test that hasn't run for 3 years.
    [marinersk]: Corion Yes, sometimes whitespace in column headers is acceptable, but I still consider it be less than desireable if that query might get revectored for an ETL-esque process...
    [marinersk]: choroba++

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