meonkeys has asked for the wisdom of the Perl Monks concerning the following question:

2001-03-03 Edit by Corion : Changed title, see first reply for real question.

  • Comment on How would I do an inplace edit, prepending '~foo' to every key of a hash? (was: How would I do an inplace edit, prepending)

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Re: How would I do an inplace edit, prepending ~foo to every key of a hash?
by chipmunk (Parson) on Feb 09, 2001 at 03:10 UTC
    Here's a solution that uses map: 
    use strict;
                
my %hash = (
    one => 'blah',
    two => 'echo',
    thr => 'aaaak',
);
                
my %new_hash = map { ("~foo$_", $hash{$_}) } keys %hash;

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      Beautiful. Simple. ++. Thanks!
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Re: How would I do an inplace edit, prepending
by meonkeys (Chaplain) on Feb 09, 2001 at 03:06 UTC
    The complete question was:
    How would I do an inplace edit, prepending "~foo" to every key of a hash?

    So here's a kludge I came up with, but I'd like to do it with a map. 
    use strict;
 
my %hash = (
   one => 'blah',
   two => 'echo',
   thr => 'aaaak',
);
 
foreach my $key (keys %hash) {
  $hash{"~foo".$key} = $hash{$key};
  delete $hash{$key};
}
 
use Data::Dumper;
print Dumper(\%hash);

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        You know I ++ed that japhy and then decided that it was truly evil. OTOH at least it isn't in void context, eh? This helps the unclean feeling a bit: 
        $hash{"~foo$_"} = delete $hash{$_} for keys %hash;

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        --
        $you = new YOU;
        honk() if $you->love(perl)

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Re: How would I do an inplace edit, prepending
by Fastolfe (Vicar) on Feb 09, 2001 at 03:11 UTC
    Update: Disregard -- a follow-up "answer" to this question provided more detail.

    Your question is rather vague, and has absolutely nothing to do with hashes. I suspect you might be looking for this: 

    perl -pi.bak -e 'print "prepended\n" if $. == 1' file1 file2 ... filen

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    Otherwise, consider posting your question in Seekers of Perl Wisdom and provide a bit more detail.
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Re: How would I do an inplace edit, prepending
by coolmichael (Deacon) on Feb 10, 2001 at 11:45 UTC
    perl -pi.bak -e "print qq(this is a test\n) if ($.==1);" data.txt

    All I did was look at perldoc:perlrun. I seem to remember something else about prepending stuff to a file somewhere on perl monks. It can't be that easy can it?

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