Hi BrowserUk,

I'm still running into trouble. Here is my code: 

#!/usr/bin/perl -w
use strict;
use Data::Dump qw[ pp ];

open my $fh, '<', 'numbs.dat' or die $!;

my $pick = genPicker( $fh ); ## Reads the file and generates a picker

sub genPicker {
    my $fh = shift;
    my( @vals, @odds ); ( $vals[ @vals ], $odds[ @odds ] ) = split( ' 
+' ) for <$fh>;

    ## Sort if not sorted
    my @order = sort{ $odds[ $a ] <=> $odds[ $b ] } 0 .. $#odds;
    @odds = @odds[ @order ];
    @vals = @vals[ @order ];

    ## Calculate and accumulate break points
    my $t = 0; $t += $_ for @odds;
    $_ /= $t for @odds;
    $odds[ $_ + 1 ] += $odds[ $_ ] for 0 .. $#odds - 1;

    ## Generate a subroutine to do the picking
    return sub {
        my $r = rand();
        $r < $odds[ $_ ] and return $vals[ $_ ] for 0 .. $#odds;
    };
}

close $fh;

[download]

Here is my numbs.dat file (I changed the numbers to simplify things):

A 0.0001
B 0.0004
C 0.0008

[download]

For what it's worth, there is a new line after each row except the last, and each letter is separated from the corresponding number by a single space. I think something is going wrong with my split, because if I pause the script and look into the variables, my @odds array has three slots, each of which is undefined, whereas my @vals array has three slots, each of which contains a letter, a space, a number and then for the first two slots a new line character.

Do you see what's wrong?

Best wishes,

Eric

In reply to Re^6: an algorithm to randomly pick items that are present at different frequencies by efoss
in thread an algorithm to randomly pick items that are present at different frequencies by efoss

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