#!/usr/bin/perl -w

use strict;

#
# This creates a list of ten strings, with index 0 corresponding to
# "zero", etc.
#
my @numbers = qw(zero one two three four five six seven eight nine);

#
# Note that we can combine the chomp statement with reading from STDIN
# in this way:
#
print "Enter a string containing a number: ";
chomp(my $answer = <STDIN>);

#
# Using split with the empty string splits between each character
#
my @characters = split "", $answer;

#
# Loop through each character...
#
foreach my $char (@characters)
{
    #
    # Note: Modifying $char changes the element in @characters
    # automatically!
    #
    $char = $numbers[$char]
        if ($char ge "0" && $char le "9");
}

#
# Using an array inside a double-quoted string causes a space to be
# inserted between each element
#
print "The output is: @characters\n";