Task #1 is here: Perl Weekly Challenge 365, Task 1
#!/usr/bin/env perl
use v5.38;
=head1 COMMENTS
Task 1: Alphabet Index Digit Sum
You are given a string $str consisting of lowercase English letters, and an integer $k.
Write a script to convert a lowercase string into numbers using alphabet positions (a=1 . . z=26),
concatenate them to form an integer, then compute the sum of its digits repeatedly $k times,
returning the final value.
=cut
# Very basic, a plain vanilla hash of arrayrefs
my %examples = ( Example_1 => [ "abc", 1 ],
Example_2 => [ "az" , 2 ],
Example_3 => [ "cat", 1 ],
Example_4 => [ "dog", 2 ],
Example_5 => [ "perl", 3 ],
);
# Laboriously creating our lookup table at the keyboard, I suspect
# the cool kids will have derived some devilishly clever ways to accomplish
# this with much less data entry. Who knows, there may even be a CPAN module
# that provides this function?
my %lut = ( a => 1, b => 2, c => 3, d => 4, e => 5, f => 6, g => 7, h => 8, i => 9,
j => 10, k => 11, l => 12, m => 13, n => 14, o => 15, p => 16, q => 17,
r => 18, s => 19, t => 20, u => 21, v => 22, w => 23, x => 24, y => 25, z => 26 );
foreach my $example ( sort keys %examples ) {
my ( $str, $k, ) = $examples{$example}->@*;
my $int = q{};
# Getting a bit lazy and using the builtin
# loop variable instead of declaring our own
# Don't try this at home with your production code
foreach ( split(//, $str) ) {
$int .= $lut{$_};
}
# When $int only contains a single numeral then we no
# longer need to call our subroutine
for (1..$k) {
# The subroutine gets called on the return value of the
# subroutine until output is complete
$int = add_them_up( $int ) if length $int > 1;
}
print "$example\n";
print "Input: \$str = \"", $str, "\", \$k = ", $k, "\n";
print "Output: $int\n\n";
}
# Very old school
# I would not be surprised to learn that there is some nifty way to
# calculate this with fewer coding key strokes.
sub add_them_up {
my $int = shift @_;
my @digits = split(//, $int );
my $sum = 0;
foreach ( @digits ) {
$sum += $_;
}
return $sum;
}
__END__
Results from running this Script:
Example_1
Input: $str = "abc", $k = 1
Output: 6
Example_2
Input: $str = "az", $k = 2
Output: 9
Example_3
Input: $str = "cat", $k = 1
Output: 6
Example_4
Input: $str = "dog", $k = 2
Output: 8
Example_5
Input: $str = "perl", $k = 3
Output: 6
Task #2 is here: Perl Weekly Challenge 365, Task 2
#!/usr/bin/env perl
use v5.38;
=head1 COMMENTS
Task 2: Valid Token Counter
You are given a sentence.
Write a script to split the given sentence into space-separated tokens and count how many are valid words.
A token is valid if it contains no digits, has at most one hyphen surrounded by lowercase letters,
and at most one punctuation mark (!, ., ,) appearing only at the end.
/ / / / / / / / / / / / / / / / / / / / / / / / / / / /
Okay, we need to build up a regex pattern match. The beginning and end are fairly straightforward
^[a-z]+ will match one or more lc letters at the start
[!.,]?$ will match one optional punctuation mark, but only at the end of the pattern
In the middle there is one, optional, hyphen which then has to have one or more lc letters.
My first attempt at this did not work for all of the examples:
-?[a-z]+
but after some research, testing, and trial and error, I ended up with this instead:
(?:-[a-z]+)? so the hyphen is optional, but if there is a hyphen, you need to have at least one
(or more) letters.
Putting them all together, this now works correctly with all of the examples:
^[a-z]+(?:-[a-z]+)?[!.,]?$
=cut
my %examples = ( Example_1 => "cat and dog",
Example_2 => "a-b c! d,e",
Example_3 => "hello-world! this is fun",
Example_4 => "ab- cd-ef gh- ij!",
Example_5 => "wow! a-b-c nice.",
);
foreach my $example ( sort keys %examples ) {
my $str = $examples{$example};
my @tokens = split(/\s/, $str);
# we will autoincrement this every time we find a valid match
my $valid_word_count = 0;
foreach my $token ( @tokens ) {
# numerals are not allowed in valid tokens
next if $token =~ m/[0-9]/;
if ( $token =~ m/^[a-z]+(?:-[a-z]+)?[!.,]?$/ ) {
$valid_word_count++;
}
}
print "$example\n";
print "Input: \$str = \"", $str, "\"\n";
print "Output: $valid_word_count\n\n";
}
__END__
Results from running this Script:
Example_1
Input: $str = "cat and dog"
Output: 3
Example_2
Input: $str = "a-b c! d,e"
Output: 2
Example_3
Input: $str = "hello-world! this is fun"
Output: 4
Example_4
Input: $str = "ab- cd-ef gh- ij!"
Output: 2
Example_5
Input: $str = "wow! a-b-c nice."
Output: 2
