Perl Weekly Challenge 332: quick and easy

This post presents my solutions to the Perl Weekly Challenge 332.
I keep doing the Perl Weekly Challenge in order to mantain my coding skills in good shape, as well as in order to learn new things, with particular regard to Raku, a language that I love.
This week, I solved the following tasks:
The PL/Perl implementations are very similar to a pure Perl implementation, even if the PostgreSQL environment could involve some more constraints. Similarly, the PL/PgSQL implementations help me keeping my PostgreSQL programming skills in good shape.

Raku Implementations

PWC 332 - Task 1 - Raku Implementation

The first task was about traducing an incoming date in the format YYYY-MM-DD into a binary numeric representation. 

sub MAIN( Str $date where { $date ~~ / ^ \d ** 4 '-' \d ** 2 '-' \d ** 2 $/ } ) {
    my @bins;
    for $date.split( '-' ) {
		@bins.push: $_.Int.base( 2 );
    }

    @bins.join( '-' ).say;
}


Quite simple: I split the string into its numerical parts, convert every number into a binary value with base and rejoin the result.

PWC 332 - Task 2 - Raku Implementation

The second task was about to find out if a given string has only unique letters. 

sub MAIN( Str $string ) {
    my $bag = Bag.new: $string.comb;
    'false'.say and exit if ( $bag.values.grep( * > 1 ) );
    'true'.say;
}


A Bag does the trick, since it can be indexed by the single letter and it counts the occurrencies. Hence, if the values are not set to 1, at least one letter is repeated.

PL/Perl Implementations

PWC 332 - Task 1 - PL/Perl Implementation

Similar to Raku, split the string, convert using sprintf and rejoin the resulting values. 

CREATE OR REPLACE FUNCTION
pwc332.task1_plperl( text )
RETURNS text
AS $CODE$

   my ( $date ) = @_;
   my @bins;

   for ( split /[-]/, $date ) {
       push @bins, sprintf( '%b', $_ );
   }

   return join( '-', @bins );

$CODE$
LANGUAGE plperl;


PWC 332 - Task 2 - PL/Perl Implementation

Use an hash to implement the same bag behavior. 

CREATE OR REPLACE FUNCTION
pwc332.task2_plperl( text )
RETURNS boolean
AS $CODE$

   my ( $string ) = @_;
   my $bag = {};

   for ( split //, $string ) {
       $bag->{ $_ }++;
   }

   return 0 if ( grep { $_ > 1 } values $bag->%* );
   return 1;

$CODE$
LANGUAGE plperl;


PostgreSQL Implementations

PWC 332 - Task 1 - PL/PgSQL Implementation

A single query can do the trick! 

CREATE OR REPLACE FUNCTION
pwc332.task1_plpgsql( d date )
RETURNS text
AS $CODE$
   SELECT string_agg( v::int::bit( 8 )::text, '-' )
   FROM   regexp_split_to_table( d::text, '-' ) v;

$CODE$
LANGUAGE sql;


PWC 332 - Task 2 - PL/PgSQL Implementation

Again, a single query can do the trick. 

CREATE OR REPLACE FUNCTION
pwc332.task2_plpgsql( t text )
RETURNS boolean
AS $CODE$
   select NOT exists(
   	  select v
	  from regexp_split_to_table( t, '' ) v
	  group by v
	  having count(*) > 1 );
$CODE$
LANGUAGE sql;


I split to a table the text, and search for repreated values.

Java Implementations

PWC 332 - Task 1 - PostgreSQL PL/Java Implementation

I misnumbered the tasks! This is the second task. 

    public static final boolean task1_pljava( String text ) throws SQLException {
		logger.log( Level.INFO, "Entering pwc332.task1_pljava" );

		Map<String, Integer> bag = new HashMap<String, Integer>();
		boolean ok = true;

		for ( String c : text.split( "" ) ) {
		    bag.putIfAbsent( c, 0 );
		    bag.put( c, bag.get( c ) + 1 );
		    if ( bag.get( c ) > 1 )
				ok = false;
		}

		return ok;

    }


As in PL/Perl, use a Map to implement a bag.

PWC 332 - Task 2 - PostgreSQL PL/Java Implementation

This is the first task! 

    public static final String task2_pljava( String date ) throws SQLException {
		logger.log( Level.INFO, "Entering pwc332.task2_pljava" );

		String result = "";
		int dashes = 2;
		for ( String current : date.split( "-" ) ) {
		    result += Integer.toBinaryString( Integer.parseInt( current ) );
		    if ( dashes > 0 ) {
				result += "-";
				dashes--;
		    }
		}

		return result;
    }


I use toBinaryString against the part of the string converted in Integer.

Python Implementations

PWC 332 - Task 1 - Python Implementation

Similar to the other implementations 

import sys
import re

# task implementation
# the return value will be printed
def task_1( args ):
    bins = []
    for c in re.split( r'[-]', args[ 0 ] ) :
        bins.append( "{0:b}".format( int( c ) ) )

    return '-'.join( bins )

# invoke the main without the command itself
if __name__ == '__main__':
    print( task_1( sys.argv[ 1: ] ) )


I use a regular expression to split the string and format to convert the string value from an integer into a string of bits.

PWC 332 - Task 2 - Python Implementation

Implement a bag behavior with a dictionary. 

import sys

# task implementation
# the return value will be printed
def task_2( args ):
    bag = {}
    for c in args[ 0 ]:
        if not c in bag:
            bag[ c ] = 0
        bag[ c ] = bag[ c ] + 1

    for x in bag:
        if bag[ x ] > 1:
            return False

    return True


# invoke the main without the command itself
if __name__ == '__main__':
    print( task_2( sys.argv[ 1: ] ) )


The article Perl Weekly Challenge 332: quick and easy has been posted by Luca Ferrari on July 31, 2025

Tags: raku , perlweeklychallenge , perl , python , java