sort using <=>

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

People of the Perl,
I have tried this code with no errors, but it is not giving me any results. My data file has 3 fileds and I am trying to sort the 3rd field, here is the data file:

05/06/04        11:01:32        E00833  
05/06/04        11:01:32        E00545  
05/06/04        11:01:32        E00820  
05/06/04        11:01:32        E00610  
05/06/04        11:01:32        E00333  
05/06/04        11:01:32        E01099  
05/06/04        11:01:32        E00213  
05/06/04        11:01:32        E00612
[download]

Below is my code:


snippett...snippett

 open (FOO, ">$scratches") || die "could not open file:$!";
        open (D, "$logf") || die "could not open file:$!";
       
         while (<D>) {

                ## look for 9840S and ebexpire
                ## declare OFS = tab  ## tell split to split on IRS 0,
+ 1 & 5. Very similar to awk print $

                if (($_ =~ /9840S/) && ($_ =~ /ebexpire, ebexpire/ )) 
+{
                        local $, = "\t";
                        print +(split)[0,1,5], $/;
                        
                } # end if
        } # end while
        
        foreach (<D>) {
                
                print FOO (sort { $a <=> $b } $_ )
        }
        close (FOO);
        close (D);
[download]

My out file is zero bytes! Help!
thanks
drock _{janitored by ybiC: Balanced <code> tags around sample data, as per consideration}

Comment on sort using <=> Select or Download Code

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Re: sort using <=>
by Happy-the-monk (Canon) on Aug 13, 2004 at 18:29 UTC

... } # end while seek(D, 0,0); # add this to rewind <D> before reusing it. foreach (<D>) { ...

Maybe rethink if you need a while loop first and a foreach loop next?
What do you expect the sort to do actually?

Update:

The solution to get the ... splitted in the second print line is simply to use split there too:

print F00 +(split)[0,1,5], $/; print FOO (sort { $a <=> $b } +(split /\s+/, $_)[0,1,5] );

Cheers, Sören

[reply]

Re^2: sort using <=>

by drock (Beadle) on Aug 13, 2004 at 18:57 UTC

open (FOO, ">$scratches") || die "could not open file:$!";
        open (D, "$logf") || die "could not open file:$!";

         while (<D>) {

                ## look for 9840S and ebexpire
                ## declare OFS = tab
                ## tell split to split on IRS 0, 1 & 5. Very similar t
+o awk print $

                if (($_ =~ /9840S/) && ($_ =~ /ebexpire, ebexpire/ )) 
+{
                        local $, = "\t";
                        print F00 +(split)[0,1,5], $/;
                        print FOO (sort { $a <=> $b } $_ );

                } # end if
        } # end while

        close (FOO);
        close (D);
[download]

[reply]
[d/l]

Re^3: sort using <=>

by Roy Johnson (Monsignor) on Aug 13, 2004 at 20:22 UTC

Schwartzian Transform

#open your files as before, then
print FOO map { $_->[1] }
          sort { $a->[0] <=> $b->[0] }
          map {my @F=split; [substr($F[2],1), $_]}
          <D>;
#close your files as before
[download]

Updated to work on the data provided.

Caution: Contents may have been coded under pressure.

[reply]
[d/l]

Re: sort using <=>
by VSarkiss (Monsignor) on Aug 13, 2004 at 18:35 UTC

Are you wondering why the second loop (the foreach) isn't doing anything? It's because you only come out of the while loop above it after reading everything out of the D filehandle, so the foreach over the same handle will never enter the block.

I'm not sure exactly what you're trying to do, so I'm not sure how to tell you to fix it. But that's the reason you're not getting anything written to FOO.


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