querybregarding array utils module in perl

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

I am using array util package for array comparison.I have reading two file single and single 2 in difference2.pl and comparing but it is showing the only the element present in array c.Plz tell me where I am doing mistake.

use Array::Utils qw(:all);

$file = 'single.txt';
open(FILE,$file);
@array= <FILE>;
#print @array;
$file1='single1.txt';
open(FILE1,$file1);
@array1=<FILE1>;







@d=@array1;
@c=@array;
print @d;
print @c;


        # symmetric difference
        @diff = array_diff(@a, @b);

        # intersection
         @isect = intersect(@c, @d);
        #print @isect;
        
        # unique union
        @unique = unique(@a, @b);
        #print @unique;

        
        # check if arrays contain same members
        if ( !array_diff(@a, @b) ) {
                # do something
        }
        
        # get items from array @a that are not in array @b
        @minus = array_minus( @c,@d );
        
        print  "\n difference";
        print  @minus;
[download]

I want the output of @minus.But is is showing the array c. Single file contains element :1,2,3,4 Single1 file contains element :1,5,6,7 Ideally the output should be:2,3,4. plz help me.

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Re: querybregarding array utils module in perl by tangent (Parson) on Jun 26, 2014 at 15:31 UTC
If your files contain a single line with the array elements separated by commas then you will need to split the line, otherwise @array will contain just a single element ("1,2,3,4") and @array1 will also contain just a single element ("1,5,6,7"). Try reading the files in this way: `use strict; use warnings; use Array::Utils qw(:all); my $file = 'single.txt'; my $file1 = 'single1.txt'; my $fh; my @array; open($fh,"<",$file) or die("Could not open $file: $!"); while (my $line = <$fh>) { chomp $line; next unless $line; push(@array, split(',',$line) ); } close($fh); my @array1; open($fh,"<",$file1) or die("Could not open $file1: $!"); while (my $line = <$fh>) { chomp $line; next unless $line; push(@array1, split(',',$line) ); } close($fh);` [download]	[reply] [d/l]
Re: querybregarding array utils module in perl by kennethk (Abbot) on Jun 26, 2014 at 15:33 UTC
Are you sure your arrays contain what you think they do? See Basic debugging checklist. Since you haven't provided your literal input files wrapped in `<code>` tags (see How do I post a question effectively?), it's hard to be helpful. Two possibilities I see: Your second open is failing, and thus you don't know that `@array1` is empty. It's probably better if your opens look more like: `open(FILE,'<', $file) or die "Open fail on $file: $!"` Your input is literally `1,2,3,4` and so your arrays only have 1 element. In this case, you need to reformat your input files to be newline separated or feed the input through split. The following code works for me. `#!/usr/bin/perl -w use strict; use Array::Utils qw(:all); my @first = (1,2,3,4); my @second = (1,5,6,7); my @minus = array_minus( @first,@second ); for my $term (@minus) { print "'$term'\n"; }` [download] It outputs `'2' '3' '4'` [download] #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply] [d/l] [select]