Task #1 is here: Perl Weekly Challenge 360, Task 1
#!/usr/bin/env perl
use strict;
use warnings;
my @inputs = ( ["Hi", 5], ["Code", 10], ["Hello", 9], ["Perl", 4], ["A", 7], ["", 5]);
foreach my $input ( @inputs ) {
my ( $output, $pad1, $pad2, );
my ( $str, $width ) = ($input->[0], $input->[1]);
my $diff = $width - length($str);
# This approach methodically assembles the desired padded string step
# by step using Perl's concatenation operator: '.' and stores the
# manipulations in the $output variable
# if the string is empty then the output consists solely of padding
if ( length($str) == 0 ) {
$output = "*" x $width;
}
else {
# if the difference between the string length and the format width is
# even then the padding is equal on each side of the string
if ( $diff % 2 == 0 ) {
$pad1 = $diff / 2;
$pad2 = $pad1;
$output = "*" x $pad1 . $str . "*" x $pad2;
}
# but if the difference is odd, then we need adjust the number of
# padding characters on each side of the string output
else {
my $half = $diff / 2;
($pad1) = $half =~ m/(\d+)\./;
$pad2 = $diff - $pad1;
$output = "*" x $pad1 . $str . "*" x $pad2;
}
}
# My approach to printing the output shown in the challenge example
# is cumbersome, to say the least. There may be more elegant, and
# faster ways to decide what to print, and how to assemble the
# desired elements
print "Input: \$str = \"", $str, "\", \$width = ", $width, "\n";
print "Output: \"", $output, "\"\n\n";
if ( length($str) == 0 ) {
print "Text length = ", length($str), ", Width = ", $width, "\n";
print "Entire output is padding\n\n\n";
}
elsif ( length($str) == $width ) {
print "No padding is needed\n\n\n";
}
else {
print "Text length = ", length($str), ", Width = ", $width, "\n";
print "Need ", $diff, " padding characters total\n";
print "Left padding: ", $pad1;
$pad1 > 1 ? print " stars" : print " star";
print ", Right padding: ", $pad2;
$pad2 > 1 ? print " stars" : print " star";
print "\n\n\n";
}
}
exit;
Task #2 is here: Perl Weekly Challenge 360, Task 2
#!/usr/bin/env perl
use strict;
use warnings;
=head1 Context
This week for Task #2 we are using a minimalist, idiosyncratic Perl-ish approach
(which may, or may not be considered idiom).
For a Perl Pro this is probably a recognizable treatment of the problem. If this is the
first time you've seen a Perl script, you'll probably get a headache.
First, we declare an array data structure named @sentences, where each
element in the array is a separate sentence from the examples in the task definition.
Instead of iterating over the array elements inside a { block } (a typical way),
we are placing the foreach iterator in the so-called post-fix location, after
our code statements.
Instead of explicitly declaring an iterator variable, we are using the default
Perl variable, "$_" (which I call dollar underscore) (also named "$ARGV"). "$_" can be thought of
as "It" (the thing that we are working on with our code statements). NOTE: by default split(),
like many, many, Perl functions, uses the content of "$_", as its input,
even if we do not explicitly include "$_" inside the parentheses.
So the only place where we explicitly included "$_" in the single line of code is as one of the
targets of our print, so that the starting sentence gets displayed in the output.
Instead of using three separate statements, e.g.,
1. split this array element on one (or more) whitespace characters (and store it in a new array, right?),
2. sort the elements in the new array (using the custom sort ),
followed by
3. a print statement that uses a join(),
We are sorting the output of the split() manipulation in place, and immediately joining those sorted
elements back together for printing to STDOUT.
The rest is just pretty-printing (formatting), with a lot of backslashes to escape the double quotes I want,
and instead of using two sequential "print"s I combined them into a single one (there is an embedded newline
character so that the output for each example appears over two printed lines).
In summary, we have a list of different sentences. We want to process the sentences in order,
one-by-one, and:
split the sentence on the whitespace between each word,
sort the words alphabetically,
join the sorted words back together,
print out the sorted version of the sentence
=cut
my @sentences = ( "The quick brown fox", "Hello World! How are you?", "Hello", "Hello, World! How are you?", "I have 2 apples and 3 bananas!");
print "Input: \$str = \"", $_, "\"\n", "Output: \"", join(" ", sort { lc($a) cmp lc($b) } split(/\s+/)), "\"\n\n" foreach ( @sentences );
exit;
