📘 Building the Pascal triangle using Perl 6

Generate the numbers of the Pascal triangle and print them. The Pascal triangle is a sequence of rows of integers. It starts with a single 1 on the top row, and each following row has one number more, starting and ending with 1, while all of the other items are the sums of the two … Continue reading “📘 Building the Pascal triangle using Perl 6”

📘 Building the product table using Perl 6

Generate and print the product table for the values from 1 to 10. The task does not say anything about how to format the output. First, let us print the results as a list with one line per one multiplication. In Perl 6, there is a cross operator X, which operates over lists and creates a … Continue reading “📘 Building the product table using Perl 6”

📘 Counting hash values in Perl 6

Having a hash, count the number of occurrences of each of its values. For example, a hash is a collection mapping a car’s license plate to the colour of the car or a passport number to the name of the street where the person lives. In the first example, the task is to count how … Continue reading “📘 Counting hash values in Perl 6”

📘 Sort hashes by parameter using Perl 6

Sort a list of hashes using data in their values. This task is commonly performed to sort items where the sortable parameter is one of the values in the hash, for example, sorting a list of people by age. my @people = (    {        name => ‘Kevin’, age => 20,    },    . . .    {        name => ‘Amanda’, age => 19,    },);@people.sort({    %^a<age> … Continue reading “📘 Sort hashes by parameter using Perl 6”

📘 How to transpose a matrix in Perl 6

Take a matrix and print its transposed version. A matrix can be represented by nested arrays or lists. For example, here’s a square 2×2 matrix: my @matrix = [1, 2],             [3, 4]; This is how the transposed matrix should look: [[1, 3],[2, 4]] Actually, the outer pair of square brackets, could be added to the initializer of the @matrix variable. … Continue reading “📘 How to transpose a matrix in Perl 6”

📘 Variadic parameters in a sub in Perl 6

Pass a few scalars to a sub and work with them as with an array inside the sub. The task is to take a few scalar parameters and pass them to a single array in the subroutine.  Here is an example of how to do that, prefixing an array name with a star: sub h($sep, … Continue reading “📘 Variadic parameters in a sub in Perl 6”

📘 Passing arrays to subroutines in Perl 6

Pass data, contained in an array, to a subroutine. In Perl 6, an array can be passed to a subroutine as easily as a scalar. You simply define it in a signature and pass it together with other arguments. my @colours = <red green blue>;sub f(@data, $sep) {    @data.join($sep).say;}f(@colours, ‘, ‘); # Prints: red, green, blue The @colours array … Continue reading “📘 Passing arrays to subroutines in Perl 6”

📘 Increasing sequences in Perl 6

Check if the given array contains increasing (or decreasing) numbers. Given the list of numbers in an array, the task is to tell if all of them are sorted in ascending or descending order. Take an array: my @data = 3, 7, 19, 20, 34; In Perl 6, reduction operators offer a very expressive and … Continue reading “📘 Increasing sequences in Perl 6”

📘 Finding minimum and maximum using Perl 6

Find the minimum and the maximum numbers in the given list of integers. Finding the minimum and maximum elements of arrays is extremely easy in Perl 6. For iterable objects, the two methods, min and max, are defined. my @list = 7, 6, 12, 3, 4, 10, 2, 5, 15, 6, 7, 8, 9, 3;say @list.min;say @list.max; For the … Continue reading “📘 Finding minimum and maximum using Perl 6”

📘 Finding unique elements using Perl 6

Print all unique elements of the given array. In Perl 6, objects of the Array type have the unique method. my @a = 2, 3, 7, 4, 5, 5, 6, 2, 10, 7;say @a.unique; The result of running this program is a sequence containing the unique elements: (2 3 7 4 5 6 10). Notice that the values … Continue reading “📘 Finding unique elements using Perl 6”