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Re^3: Stupid mistakes I repeatedly make

by jhourcle (Prior)
on Mar 28, 2005 at 20:36 UTC ( #442946=note: print w/ replies, xml ) Need Help??

in reply to Re^2: Stupid mistakes I repeatedly make
in thread Stupid mistakes I repeatedly make

s/something/else/ for @list;

But, how do you accomplish the same thing with map, and does it make any difference?

my @new_list = map { ( my $tmp = $_) =~ s/.../.../; $tmp  } @list;

It's useful only for those times when you don't want to corrupt the original list, for whatever reason

You could probably also do:

@list = map { s/.../.../; $_ } @list;

but you'd take a performance hit for building the list in memory, I would think. (I haven't benchmarked it).

Update: Anonymous makes a good point -- faster not to assign it back to itself. (but there is still a performance hit as compared to for/foreach, so just use one of those, and only use map if you don't want to corrupt the original).

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Re^4: Stupid mistakes I repeatedly make
by Anonymous Monk on Mar 29, 2005 at 11:54 UTC
    If you just want to modify the list:
    map {s/.../.../} @list;
    and in modern Perls, that won't build a list in memory.

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