On 5/11/10 Tue May 11, 2010 1:52 PM, "Harry Putnam" <rea...@newsguy.com>
scribbled:
> Shawn H Corey <shawnhco...@gmail.com> writes:
>
>> Harry Putnam wrote:
>>> But, is there an easier way?
>>
>> Invert both hashes and find the keys in both inverses.
>
> Shawn, hoping to pester you once more about this topic.
It is not fair to single out Shawn for help. Just post your question and
hope for a response.
> %d1h is made up like this
>
> this is key this is value
> $File::Find::name = $_
The use of the equal sign '=' in the above makes it look like you are
assigning a value to $File::Find::name. It is better to stick to Perl
syntax:
$d1h{$File::Find::name} = $_;
for example:
$d1h{'./dir1/sub/fname'} = 'fname';
> So cutting to the chase, I try to take advantage of your inversion
> code. It seems to work well, but I'm not confident enough to know
> if there are possible hidden gotchas someone with more experience
> might see right off the bat.
>
> ------- --------- ---=--- --------- --------
> Some selective output first:
>
> [...]
>
> d1 ./dir1/etc/images/gnus/exit-summ.xpm
> d2 (1) ./dir2/etc/images/gnus/exit-summ.xpm
>
> d1 ./dir1/etc/images/gnus/reply.xpm
> d2 (1) ./dir2/etc/images/mail/reply.xpm
> d2 (2) ./dir2/etc/images/gnus/reply.xpm
>
> d1 ./dir1/etc/images/gnus/README
> d2 (1) ./dir2/src/m/README
> d2 (2) ./dir2/etc/e/README
> [...]
> d2 (47) ./dir2/doc/lispintro/README
>
> d1 ./dir1/lisp/gnus-util.el
> d2 (1) ./dir2/lisp/gnus/gnus-util.el
You can use the Unix file command (if you are on Unix) to find the files
with a certain name:
find dir1 -name README
etc. to check the results of your program.
Your program below looks fine. I see no obvious defects. You can generate
the inverted hashes in the find routines (see below). You can use the
inverted hashes only (see below).
> #!/usr/local/bin/perl
>
> use strict;
> use warnings;
> use File::Find;
> #use diagnostics;
>
> my %d1h;
> my %d2h;
> my $d1tag = 'd1';
> my $d2tag = 'd2';
>
> ## Make sure we are feed two directory names
> ( my ( $d1, $d2 ) = @ARGV ) == 2
> or die "\nUsage: $0 ./dir1 ./dir2\n";
>
> ## Make sure incoming directory names exist
> for ($d1, $d2 ){
> ( -d ) or die "<$_> cannot be found on the file system";
> }
>
> ## Build the hashs
>
my( %inv_d1h, %inv_d2h );
> find sub {
> return unless -f;
> $d1h{ $File::Find::name } = $_;
push( @{$inv_d1h{$_}}, $File::Find::name );
> },$d1;
>
> find sub {
> return unless -f;
> $d2h{ $File::Find::name } = $_;
push( @{$inv_d2h{$_}}, $File::Find::name );
> },$d2;
>
> ## Invert 1 hash and it needs to be the second one on cmd line
> my %inv_d2h = invert( \%d2h );
>
> sub invert {
> my $h = shift @_;
> my %inv = ();
>
> while( my ( $k, $v ) = each %{ $h } ){
> push @{ $inv{$v} }, $k;
> }
> return %inv;
> }
>
> ## Could have used `values' of %d1h here for $value (values %d1h)
> ## and avoided things like `...@{ $inv_d2h{ $d1h{ $key } } }',
> ## which would then be `...@{ $inv_d2h{ $value } }' but would
> ## not then have such ready access to the `keys' which are
> ## needed here too, and will be needed later on (not shown here)
> ## for now we just print to show how it works.
>
> foreach my $key ( keys %d1h ){
> if(exists $inv_d2h{ $d1h{ $key } }){
> print " $d1tag $key\n";
>
> ## separate counter to keep (my) confusion down
> my $matchcnt = 0;
> for ( @{ $inv_d2h{ $d1h{ $key } } } ) {
> print " $d2tag (" . ++$matchcnt .") $_\n";
> }
> print "\n";
> }
> }
>
Using only "inverted" hashes (untested):
for my $file ( sort keys %inv_d1h ) {
if( exists $inv_d2h{$file} ) {
print "Duplicate file names found: ", scalar @{$inv_d1h{$file}},
" in $d1 and ", scalar @{$inv_d2h{$file}}, " in $d2\n";
print "\n$d1:\n ", join("\n ",@{inv_d1h{$file}}), "\n";
print "\n$d2:\n ", join("\n ",@{inv_d2h{$file}}), "\n";
}
}
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