Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic

Re: finding unique items in an array, from a text file

by andye (Curate)
on Jan 13, 2009 at 19:28 UTC ( #736054=note: print w/replies, xml ) Need Help??

in reply to finding unique items in an array, from a text file

hiya - looks a bit overcomplicated, should be really simple. IMHO you don't need @lines, @uniq and %seen... only need one hash to do this.

I'd prefer to do something like this (off the top of my head, code not tested):

# open the file into FH my %uniq; $uniq{$_} = 1 while (<FH>); print join "\n", keys %uniq; # close the file

Hope that helps. All the best.

Replies are listed 'Best First'.
Re^2: finding unique items in an array, from a text file
by johngg (Abbot) on Jan 13, 2009 at 23:27 UTC

    I think there might be a couple of problems with your code.

    • You join the output with \ns but you did not chomp the input so you will get extra blank lines.
    • Hash keys are unordered so the line order of the original file will be scrambled. This may or may not be an issue.

    The grep solutions suggested might be better if line order is to be preserved. Something like (again, not tested).

    ... my %seen = (); print grep ! $seen{ $_ } ++, <$fh>; ...



      All good points. ;)

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://736054]
[Discipulus]: nice Perl dreams, folks.. shower->Dumas->bed
[erix]: pere ou fils?
[Lady_Aleena]: Discipulus, good night.
[Discipulus]: pere, le vicomte de bragelonne.. wonderfull
[erix]: I'll keep that in mind (haven't read), buona notte :)
[Discipulus]: oh erix but is the fourth of cycle;read them in order
[erix]: hm, perhaps I can just read it here
Discipulus zzz...

How do I use this? | Other CB clients
Other Users?
Others contemplating the Monastery: (12)
As of 2017-05-23 20:01 GMT
Find Nodes?
    Voting Booth?