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

Two related questions:
1. What is the best way to find the minimum value in a list ? (sort @_)[0] is clean, but seems wasteful. I'm surprised there doesn't seem to be a built-in MIN function. Is there a clever way with map and a?b:c or something ?
2. What is the best way to find the INDEX of the minimum value in a list ? (If there are duplicates, any of their indecies are OK).
Thanks :)

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Re: find minimum in list
by broquaint (Abbot) on Feb 10, 2004 at 14:00 UTC
    Check out List::Util which became a core module as of 5.7.3 
    my $min   = min @list;
my $idx   = first { $list[$_] == $min } 0 .. $#list;
## or for duplicates
my(@idxs) =  grep { $list[$_] == $min } 0 .. $#list;

    [download]
    HTH

    _________
    broquaint

[reply]
[d/l]
      Great tips, thanks!
[reply]
Re: find minimum in list
by Limbic~Region (Chancellor) on Feb 10, 2004 at 14:02 UTC
    Anonymous Monk,
    While there is a module that has just the function you are looking for, your second question leads me to offer the "low water mark" solution. 
    #!/usr/bin/perl
use strict;
use warnings;

my @list = qw(4 78 3 89 4 1000 5);

my %minimum;
for my $index ( 0 .. $#list ) {
   @minimum{ qw(index min) } = ($index , $list[$index]) if ! %minimum;
   if ( $list[$index] < $minimum{min} ) {
       @minimum{ qw(index min) } = ($index , $list[$index]);
   }
}
print "The index of the smallest number is : $minimum{index}\n";
print "The valud of the smallest number is : $minimum{min}\n";

    [download]
    Cheers - L~R
[reply]
[d/l]
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