1 files changed, 52 insertions, 6 deletions

diff --git a/ruby.html.markdown b/ruby.html.markdown
index 1883d1ad..0e798706 100644
--- a/ruby.html.markdown
+++ b/ruby.html.markdown
@@ -11,7 +11,8 @@ 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"]
+  - ["Gabriel Halley", https://github.com/ghalley"]
 ---
 
 ```ruby
@@ -38,6 +39,7 @@ You shouldn't either
 10 * 2 #=> 20
 35 / 5 #=> 7
 2**5 #=> 32
+5 % 3 #=> 2
 
 # Arithmetic is just syntactic sugar
 # for calling a method on an object
@@ -78,10 +80,14 @@ true && false #=> false
 true || false #=> true
 !true #=> false
 
-# Alternate spellings of logical operators
-true and false #=> false
-true or false #=> true
-not true #=> false
+# There are alternate versions of the logical operators with much lower
+# precedence. These are meant to be used as flow-control constructs to chain
+# statements together until one of them returns true or false.
+
+# `do_something_else` only called if `do_something` succeeds.
+do_something() and do_something_else()
+# `log_error` only called if `do_something` fails.
+do_something() or log_error()
 
 
 # Strings are objects
@@ -101,8 +107,14 @@ placeholder = 'use string interpolation'
 'hello ' + 3 #=> TypeError: can't convert Fixnum into String
 'hello ' + 3.to_s #=> "hello 3"
 
-# print to the output
+# print to the output with a newline at the end
 puts "I'm printing!"
+#=> I'm printing!
+#=> nil
+
+# print to the output without a newline
+print "I'm printing!"
+#=> I'm printing! => nill
 
 # Variables
 x = 25 #=> 25
@@ -149,6 +161,7 @@ array = [1, 2, 3, 4, 5] #=> [1, 2, 3, 4, 5]
 # Arrays can be indexed
 # From the front
 array[0] #=> 1
+array.first #=> 1
 array[12] #=> nil
 
 # Like arithmetic, [var] access
@@ -159,15 +172,25 @@ array.[] 12 #=> nil
 
 # From the end
 array[-1] #=> 5
+array.last #=> 5
 
 # With a start index and length
 array[2, 3] #=> [3, 4, 5]
 
+# Reverse an Array
+a=[1,2,3]
+a.reverse! #=> [3,2,1]
+
 # Or with a range
 array[1..3] #=> [2, 3, 4]
 
 # Add to an array like this
 array << 6 #=> [1, 2, 3, 4, 5, 6]
+# Or like this
+array.push(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:
@@ -188,6 +211,10 @@ 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
 
@@ -240,6 +267,12 @@ hash.each do |key, value|
   puts "#{key} is #{value}"
 end
 
+# If you still need and index you can use "each_with_index" and define an index
+# variable
+array.each_with_index do |element, index|
+  puts "#{element} is number #{index} in the array"
+end
+
 counter = 1
 while counter <= 5 do
   puts "iteration #{counter}"
@@ -251,6 +284,19 @@ end
 #=> iteration 4
 #=> iteration 5
 
+# There are a bunch of other helpful looping functions in Ruby, 
+# for example "map", "reduce", "inject", the list goes on. Map,
+# for instance, takes the array it's looping over, does something
+# to it as defined in your block, and returns an entirely new array.
+array = [1,2,3,4,5]
+doubled = array.map do |element|
+  element * 2
+end
+puts doubled
+#=> [2,4,6,8,10]
+puts array
+#=> [1,2,3,4,5]
+
 grade = 'B'
 
 case grade