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

Hello guys ! If i have 2 arrays; 
@a=(0,1,0,1,0,0,0,1);
@b=(0,0,1,1,0,0,0,0);

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How do i compare those two arrays whether the value on position 0 in @a is equal with the value on position 0 in @b ? i tried with this but it does not work with : 
@intersection = @difference = ();
%count = ();
foreach $element (@a, @b) { $count{$element}++ }
foreach $element (keys %count)
{
  push @{ $count{$element} > 1 ? \@intersection : \@difference }, $ele
+ment;
}
foreach (@difference)
{
 print $_."--";
}

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because it is checking whether values of elements are equal.

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Re: Compare two arrays
by davido (Cardinal) on Feb 01, 2012 at 08:32 UTC

    You want to compare each element of @a against the element of the same index in @b, right? This will do it.

    print "Index: $_ => \@a: $a[$_], \@b: $b[$_]\n" 
    for grep { $a[$_] != $b[$_] } 0 .. $#a;

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    ...or...

    foreach( 0 .. $#a ) {
    print "Index: $_ => \@a: $a[$_], \@b: $b[$_]\n" if $a[$_] != $b[$_
+];
}

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    Which you choose kind of depends on whether you're more interested in keeping a list of indices to the dissimilar elements, or simply interested in processing the mismatches one by one. The grep version is handy for getting the list of mismatches.


    Dave

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Re: Compare two arrays
by Anonymous Monk on Feb 01, 2012 at 08:33 UTC
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Re: Compare two arrays
by Anonymous Monk on Feb 01, 2012 at 08:27 UTC
    I think i found a way to do it
    my $count=0;
for ( my $i=0; $i <($#a+1);$i++)
{
 if ( $a[$i] != $b[$i] )
 {
   $count++;
 }
}
print $count;

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Re: Compare two arrays
by rustic (Monk) on Feb 01, 2012 at 13:22 UTC
    try use Algorithm::Diff
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      Hi Guys! I am very new to perl I have similar kind of problem where I need to compare 2 files , lets say : file1 contents= M|_|03-04-2012_08:21:03|_|Device1|_|8|_|Int/0.101|_| M|_|03-04-2012_08:01:05|_|Device1|_|8|_|Int/0.101|_| C|_|09-03-2011_06:49:52|_|Device3|_|192.165.161.41^150^router|_|192.165.161.41^150^router P|_|04-04-2012_12:37:14|_|Device4_|CPU|_|CPU| File2 contents are : C|_|09-03-2011_06:49:52|_|Device5|_|cpu-1|_|cpu-1| P|_|04-04-2012_12:37:14|_|Device4|_|CPU|_|CPU C|_|09-03-2011_06:49:52|_|Device3|_|192.165.161.41^150^router|_|192.165.161.41^150^router I have some conditions which I need to chcek and then filter desired o/p , those conditions are as below : 

      if(($array1[0]=~/c/i) && ($array2[0]= ~/c/i))

{
     if ($arra1[2]=array2[2] && array1[4]=array2[4])
         {
         don't add anything 
         }
     else
        {
        append matched line to file2
        }        
        
}

elsif(($array1[0]=~/M/i) && ($array2[0]= ~/M/i))

{
       
if ($arra1[2]=array2[2] && array1[4]=array2[4])
         {
         don't add anything 
         }
     else
        {
        append matched line to file2
        }

}

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      I tried to apply this logic in below code but not working as expected , please help ! 

      #!/usr/local/bin/perl
use strict;

my @array1;
my @array2;
#my $count=0;
my $i=0;

open (OUTFILE ,">file2.dat") || die "can't create" ;


open (FILE1,"file1.dat");
while(my $value1=<FILE1>)
{
my $i= $i +1 ;
@array1=split('\|_\|',$value1);
chomp($value1);
my $dev1=$array1[2] ;
my $attribute1=$array1[4];
my $profile1=$array1[0];

open (FILE2, "file2.dat");
while (my $value2=<FILE2>)
{
  @array2=split('\|_\|',$value2);
  chomp($value2);
  my $dev2=$array2[2] ;
my $attribute2=$array2[4];
my $profile2=$array2[0];

 if(($profile1 = ~/C/i) and ($profile2 = ~/C/i))
{

           if(($dev1 = $dev2) && ($attribute1 = $attribute2))
                 {
                     $i ++  ;
                     }

            else
             {
                 print OUTFILE "$value1"   ;

              }

}
else
{
if(($profile1 = ~/M/i) and ($profile2 = ~/M/i))
{

if(($dev1 = $dev2) && ($attribute1 = $attribute2))

                 {
                     $i ++  ;
                     }

            else
             {
                 print OUTFILE "$value1"   ;

              }

}
}



}

}




close FILE1;
close FILE2;
close OUTFILE;

}

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