in reply to Sorting based on any column

>Trying to create a Subroutine to sort array based on any column numerically when my array is having both characters and numercis

I am not sure I completely understand the example...but this will sort alpha and numeric 

#! /usr/local/bin/perl -w

use strict;

my $data = [qw| z x y 2 1 3 |];

print 'no sort:' , @$data ,"\n";
print 'sort:   ' , (sort _sort_a_tron @$data) , "\n";

sub _sort_a_tron {  
  
  no warnings; 
  return ( $a <=> $b or $a cmp $b );   
  
} 

# output #
# no sort:zxy213
# sort:   xyz123

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Re^2: Sorting based on any column
by Laurent_R (Canon) on May 19, 2015 at 22:33 UTC
    This is basically one of the solutions I offered above, but with a number of caveats about the data.
[reply]

      Sorry for not being clear in requirement. Consider my OBJD Array data is like shown below: 

      1   ab    2   3   cd   4   5   6   6
9   rc    4   5   ef   6   3   4   1
7   fa    5   2   tg   5   9   9   0
3   bg    3   9   jh   5   2   2   1

      [download]

      I want to create a subroutine which takes two argument as input, First argument is array and second argument is column number on which sorting has to be done. Say for example sort_array is a subroutine and I pass OBJD array and column to sort as arguments. something like sort_array(\@OBJD,2) and this should provide me below output 

      1   ab    2   3   cd   4   5   6   6
3   bg    3   9   jh   5   2   2   1
9   rc    4   5   ef   6   3   4   1
7   fa    5   2   tg   5   9   9   0

      [download]

      Or something like sort_array(\@OBJD,6) and this should provide me below output 

      3   bg    3   9   jh   5   2   2   1
9   rc    4   5   ef   6   3   4   1
1   ab    2   3   cd   4   5   6   6
7   fa    5   2   tg   5   9   9   0

      [download]

      Would like to do it using regular sorting method as well as using 'Schwartzian transform' just to learn it.

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[d/l]
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        It depends on whether your sample data represents an array-of-arrays, with each non-whitespace token as an element of a sub-array, or a single-level array with each line as an element. In the first case, it's fairly simple, something like this: 

        sub sort_aoa {
  my( $array, $column ) = @_;
  return sort { $a->[$column] cmp $b->[$column] } @$array;
}

        [download]

        If each element is a whole line, you'll have to split them into words before sorting. This is where a Schwartzian Transform is likely to help the most, but I'll show the basic idea and you can add that:

        sub sort_lines_by_column {
  my( $array, $column ) = @_;
  return sort {
    return( (split ' ', $a)[$column] cmp (split ' ', $b)[$column] );
  } @$array;
}

        [download]

        (Untested. In both cases, replace the 'cmp' comparison with whatever you want.)

        Aaron B.
        Available for small or large Perl jobs and *nix system administration; see my home node.

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[d/l]
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        Another piece of the puzzle: sort accepts code refs as the sorting function.

        my @l = (10, 2, 200, 23, 3, 9, 11, 1);
my $num = sub { $a <=> $b };
my $str = sub { $a cmp $b };
print join(", ", sort $num @l ), "\n";
print join(", ", sort $str @l ), "\n";
__END__
1, 2, 3, 9, 10, 11, 23, 200
1, 10, 11, 2, 200, 23, 3, 9

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[reply]
[d/l]

        The thread linked to by the other anon above contains some ideas. Personally I like Scalar::Util's looks_like_number, since AFAIK that's the same function Perl uses internally. If you know that your columns always contain either numbers xor non-numbers, testing the first value of the column should be enough to determine which comparison to use for that column. If however your columns contain a mix of numbers and non-numbers (e.g. "1 a","foo","3.14","42","b5ar","93b"), you'll have to make a decision on how to sort a column like that.

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