Thursday, February 27, 2014

Arrays and Indexers in IronRuby



Today's post is about Arrays and Indexers in IronRuby. Here below you will find a very easy to follow program, that demonstrate arrays and indexer, by implementing some simple tasks that will make you grasp the idea of those 2 features real quick. The main goal of this post, is not really teaching arrays because, come on, you probably already know "all" about them, in fact, it is more to show you how you do that in IronRuby, in this case, compared to all other 22 languages on future posts, which essentially, is the real aim behind this blog.

This is the last of the .NET dynamic languages. I'm considering to stop writing about it because the project seems to be dead with no updates since 13/03/11)... will see, probably this will be the last post about it if no news, fortunately, there is still JRuby.

By the way, if you missed my most recent post, "New Series - Arrays and Indexers", check it out. It has more details about the following program, and a bunch of definitions for the concepts used on this, and the following, posts. Or you can check my previous posts about arrays in JRuby, later on, just to compare.

I encourage you to copy the code below and try it yourself, normally, all programs you find in this blog are source code complete, just paste it on your IDE and run it.

There is room for improvement of the code, using generics is one example, but Generics, Collections, lambdas, etc. will have their own "series" of posts.


require "mscorlib" 
include System

# Console Program
def main()
    # Single-dimensional Array(s)
    print_title("Reverse Array Elements")
 
    # Declare and Initialize Array of Chars      
    letters = Array.new(5," ")
    letters[0] = "A"
    letters[1] = "E"
    letters[2] = "I"
    letters[3] = "O"
    letters[4] = "U"
 
    print_array(letters)  
    inverse_letters = reverse_char(letters)
    print_array(inverse_letters)

    print_title("Sort Integer Array Elements")
    # Declare and Initialize Array of Integers   
    numbers = [10, 8, 3, 1, 5]
    
    print_array(numbers)       
    ordered_numbers = bubblesort(numbers)   
    print_array(ordered_numbers)

    print_title("Sort String Array Elements")  
 
    # Declare and Initialize and Array of Strings 
    #names = Array.new(5, ["Damian","Rogelio","Carlos","Luis","Daniel"])
    # or just 
    names = ["Damian", 
      "Rogelio", 
      "Carlos", 
      "Luis", 
      "Daniel"]

    print_array(names)   
    ordered_names = bubblesort(names)   
    print_array(ordered_names)

    # Multi-dimensional Array (Matrix row,column)   
    print_title("Transpose Matrix")   

    # for an empty table initialized to 0s
    # matrix = Array.new(rows,0) { Array.new(cols,0) }
    matrix = [[6, 4, 24],      
              [1, -9, 8]]

    print_matrix(matrix)
    transposed_matrix = transpose_matrix(matrix)   
    print_matrix(transposed_matrix)  
 
    # Jagged Array (Array-of-Arrays)   
    print_title("Upper Case Random Array & Graph Number of Elements")   

=begin
# Creating an array of string arrays using the String.Split method   
# instead of initializing it manually as follows:   
# 
# text = [    
#  [ ["word1", "word2, "wordN"],    
#  [ ["word1", "word2, "wordN"],    
#  ...
#  ]   
#     
# Text extract from: "El ingenioso hidalgo don Quijote de la Mancha"        
=end
    text = [
    "Hoy es el dia mas hermoso de nuestra vida, querido Sancho;".split(" "),    
    "los obstaculos mas grandes, nuestras propias indecisiones;".split(" "),    
    "nuestro enemigo mas fuerte, miedo al poderoso y nosotros mismos;".split(" "),    
    "la cosa mas facil, equivocarnos;".split(" "),    
    "la mas destructiva, la mentira y el egoismo;".split(" "),    
    "la peor derrota, el desaliento;".split(" "),    
    "los defectos mas peligrosos, la soberbia y el rencor;".split(" "),    
    "las sensaciones mas gratas, la buena conciencia...".split(" ")
    ] 
 
    print_jagged_array(text)   
    uppercase_random_array(text)      
    print_jagged_array(text)   
    graph_jagged_array(text)

    # Array Exceptions
    print_title('Common Array Exceptions')
    
    print_common_array_exceptions(nil)
    print_common_array_exceptions(text)  

    # Accessing Class Array Elements through Indexer
    print_title('Alphabets')
    
    vowels = Alphabet.new(5)
    vowels[0] = "a"
    vowels[1] = "e"
    vowels[2] = "i"
    vowels[3] = "o"
    vowels[4] = "u"

    puts "\nVowels={%s}" % [vowels[0],vowels[1],vowels[2],vowels[3],vowels[4]].join(",")

    en = Alphabet.new("abcdefghijklmnopqrstuvwxyz")   

    puts "English Alphabet = {%s}" % [en]

    puts "Alphabet Extract en[9..19] = {%s}" % [Alphabet.new(en.slice(9, 10))]

    word1 = [en[6],en[14],en[14],en[3]].join("")
    word2 = [en[1],en[24],en[4]].join("")   
    word3 = [en[4],en[21],en[4],en[17],en[24],en[14],en[13],en[4]].join("")   
    puts "\n%s %s, %s!\n" % [word1, word2, word3]
 
    gets
end

def reverse_char(arr)
    arr.reverse
end 

def bubblesort(arr)  
    for i in arr.reverse
        for j in (0..arr.count-2)
            if arr[j] > arr[j + 1]    
                swap = arr[j]   
                arr[j] = arr[j + 1]   
                arr[j + 1] = swap   
            end    
        end 
    end   
    arr
end

def transpose_matrix(m)  
=begin
# Transposing a Matrix 2,3  
#     
#   A =  [6  4 24]T [ 6  1]  
#        [1 -9  8]  [ 4 -9]  
#                [24  8]  
=end
    transposed = Array.new(m[0].size) { Array.new(m.size) } 
    for i in 0..(m.size-1)   
        for j in 0..(m[0].size-1)   
            transposed[j][i] = m[i][j]
        end
    end
    transposed  
end

def uppercase_random_array(arr)      
    r = System::Random.new
    i = r.next(arr.size)
    for j in 0..(arr[i].size-1)   
        arr[i][j] = arr[i][j].upcase
    end
end

def print_array(arr)
    puts "\nPrint Array Content #{arr.GetType().Name}[#{arr.size}]"
    for i in 0..(arr.size-1)
        puts " array [%2s] = %2s" % [i, arr[i]]
    end
end

def print_matrix(m)
    puts "\nPrint Array Content #{m.GetType().Name}[#{m.size}][#{m[0].size}]"
    for i in 0..(m.size-1)
        for j in 0..(m[0].size-1)
            puts " array [%2s,%2s] = %2s" % [i, j, m[i][j]]
        end
    end
    m
end

def graph_jagged_array(arr)
=begin
# When using Arrays, we can use for(each) instead of for by index
#    for s in arr  
#        for w in s 
#        end
#    end
=end 
    puts "\nPrint Text Content #{arr.GetType().Name}"
    for i in 0..(arr.size-1)  
        line = ""
        line += "Line %2s|" % (i+1).to_s 
        for j in 0..(arr[i].size-1)   
            line += " * "
        end            
        line += "(#{arr[i].size})"
        puts line
    end
end

def print_jagged_array(arr)
    puts "\nPrint Jagged Array Content #{arr.GetType().Name}"
    for i in 0..(arr.size-1)
        line = ""
        for j in 0..(arr[i].size-1)     
            line += " " + arr[i][j]
        end
        if line == line.upcase
            line += " <-- [UPPERCASED]"
        end
        puts line
    end
end

def print_common_array_exceptions(arr)
    begin  
        arr.fetch(100)
    rescue Exception => ex
        puts "\nException: \n%s\n%s" % [ex.GetType().Name, ex.message]
    #else
    #   others
    end
end

def print_title(message)   
    puts ""  
    puts ("=" * 54)   
    puts message   
    puts ("=" * 54)
end     


class Alphabet
    # Array Field   
    @letters = []

    # Indexer Get/Set Property
    def [](idx)
        @letters[idx]
    end
    def []=(idx, value)
        @letters[idx] = value.upcase
    end
    
    # Read-Only Getter
    def length
        @letters.size
    end          

    # Constructor/Initializer
    def initialize(param)  
        if param.class == 1.class
            @letters = Array.new(param, " ")
        elsif param.class == "".class
            @letters = param.upcase.chars.to_a
        elsif param.class == [].class
            @letters = param
        else
            @letters = nil
        end
    end

    # Overridden Method    
    def to_s
        @letters.join(",")
    end
 
    # Method   
    def slice(start, length)
        @letters[start..start+length-1]
    end

end

main


The output:






















































































VoilĂ , that's it. Next post in the following days.

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