use strict;
use warnings;

use feature 'say';

display_parts( 0, 9, 10 );
display_parts( 0.022, 0.086, 10 );
display_parts( 0.123, 8.672, 10 );
display_parts( 1_123_345_456, 1_124_246_357.5, 11 );

sub display_parts {
    my $result = get_ticks(@_);

    printf "start: %s, end: %s, parts: %s\n",
        map pretty($_), @_;

    for ( 0 .. $#$result ) {
        printf "  %2d => %s\n", $_, pretty( $result->[$_] );
    }

    print "\n";
}

sub get_ticks {
    my ( $start, $end, $parts ) = @_;

    my $tick = ( $end - $start ) / ( $parts - 1 );

    my @result;
    push @result, $start;
    push @result, $result[-1] + $tick for 1 .. ($parts - 1);

    return \@result;
}

sub pretty {
    return shift =~ s/\d \K (?= (?: \d{3} )+ \b )/_/xgr;
}