Ruby Arrays 2020

Ruby arrays are ordered, integer-indexed collections of any object. Each element in an array is associated with and referred to by an index.

Ruby arrays can hold objects such as String, Integer, Fixnum, Hash, Symbol, even other Array objects. Ruby arrays are not as rigid as arrays in other languages. Ruby arrays grow automatically while adding elements to them.

One way of creating an array is with the new class method:

array_1 = Array.new

We can set the size of an array at the time of creating array:

array_2 = Array.new(3) #=> [nil, nil, nil]

We can assign a value to each element in the array as follows:

array_3 = Array.new(3, "Ruby") #=> ["Ruby", "Ruby", "Ruby"]

As a practice, here is a code for binary search:

#!/usr/bin/ruby
# bin.rb

def bin(a,n)
   s = 0
   e = a.length - 1
   mid = (s + e)/2
   while ( mid >= s and mid <= e)
      if (n < a[mid])
         e = mid - 1
      elsif (n > a[mid])
         s = mid + 1
      else
         return true
      end
      mid = (s + e)/2
   end
   return false
end

# input
arr = [1,3,5,7,9,11,13,15,17,19]

# try
find = [1,9,17,0,21,8]

find.each do |item|
   puts bin(arr,item)
end

Output:

true
true
true
false
false
false

Ruby on Rails

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