Merge pull request #1011 from iamrahil/ruby

[ruby] Array and Hash specific functions

ruby.html.markdown

@@ -11,6 +11,7 @@ contributors:
   - ["Ariel Krakowski", "http://www.learneroo.com"]
   - ["Dzianis Dashkevich", "https://github.com/dskecse"]
   - ["Levi Bostian", "https://github.com/levibostian"]
+  - ["Rahil Momin", "https://github.com/iamrahil"]
 
 ---
 
@@ -169,6 +170,9 @@ array[1..3] #=> [2, 3, 4]
 # Add to an array like this
 array << 6 #=> [1, 2, 3, 4, 5, 6]
 
+# Check if an item exists in an array
+array.include?(1) #=> true
+
 # Hashes are Ruby's primary dictionary with keys/value pairs.
 # Hashes are denoted with curly braces:
 hash = { 'color' => 'green', 'number' => 5 }
@@ -188,6 +192,10 @@ new_hash = { defcon: 3, action: true }
 
 new_hash.keys #=> [:defcon, :action]
 
+# Check existence of keys and values in hash
+new_hash.has_key?(:defcon) #=> true
+new_hash.has_value?(3) #=> true
+
 # Tip: Both Arrays and Hashes are Enumerable
 # They share a lot of useful methods such as each, map, count, and more