Merge remote-tracking branch 'adambard/master'

1 files changed, 56 insertions, 5 deletions

diff --git a/ruby.html.markdown b/ruby.html.markdown
index 7bd28d86..b7f8b4a1 100644
--- a/ruby.html.markdown
+++ b/ruby.html.markdown
@@ -12,7 +12,9 @@ contributors:
   - ["Dzianis Dashkevich", "https://github.com/dskecse"]
   - ["Levi Bostian", "https://github.com/levibostian"]
   - ["Rahil Momin", "https://github.com/iamrahil"]
-
+  - ["Gabriel Halley", "https://github.com/ghalley"]
+  - ["Persa Zula", "http://persazula.com"]
+  - ["Jake Faris", "https://github.com/farisj"]
 ---
 
 ```ruby
@@ -39,6 +41,12 @@ You shouldn't either
 10 * 2 #=> 20
 35 / 5 #=> 7
 2**5 #=> 32
+5 % 3 #=> 2
+
+# Bitwise operators
+3 & 5 #=> 1
+3 | 5 #=> 7
+3 ^ 5 #=> 6
 
 # Arithmetic is just syntactic sugar
 # for calling a method on an object
@@ -46,7 +54,7 @@ You shouldn't either
 10.* 5 #=> 50
 
 # Special values are objects
-nil # Nothing to see here
+nil # equivalent to null in other languages
 true # truth
 false # falsehood
 
@@ -74,6 +82,11 @@ false.class #=> FalseClass
 2 <= 2 #=> true
 2 >= 2 #=> true
 
+# Combined comparison operator
+1 <=> 10 #=> -1
+10 <=> 1 #=> 1
+1 <=> 1 #=> 0
+
 # Logical operators
 true && false #=> false
 true || false #=> true
@@ -106,8 +119,20 @@ placeholder = 'use string interpolation'
 'hello ' + 3 #=> TypeError: can't convert Fixnum into String
 'hello ' + 3.to_s #=> "hello 3"
 
-# print to the output
+# Combine strings and operators
+'hello ' * 3 #=> "hello hello hello "
+
+# Append to string
+'hello' << ' world' #=> "hello world"
+
+# 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! => nil
 
 # Variables
 x = 25 #=> 25
@@ -154,6 +179,7 @@ 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
@@ -164,10 +190,15 @@ 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]
 
@@ -199,8 +230,8 @@ 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
+new_hash.key?(:defcon) #=> true
+new_hash.value?(3) #=> true
 
 # Tip: Both Arrays and Hashes are Enumerable
 # They share a lot of useful methods such as each, map, count, and more
@@ -254,6 +285,12 @@ 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}"
@@ -265,6 +302,19 @@ 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
@@ -539,6 +589,7 @@ Something.new.qux # => 'qux'
 ## Additional resources
 
 - [Learn Ruby by Example with Challenges](http://www.learneroo.com/modules/61/nodes/338) - A variant of this reference with in-browser challenges.
+- [An Interactive Tutorial for Ruby](https://rubymonk.com/) - Learn Ruby through a series of interactive tutorials.
 - [Official Documentation](http://www.ruby-doc.org/core-2.1.1/)
 - [Ruby from other languages](https://www.ruby-lang.org/en/documentation/ruby-from-other-languages/)
 - [Programming Ruby](http://www.amazon.com/Programming-Ruby-1-9-2-0-Programmers/dp/1937785491/) - An older [free edition](http://ruby-doc.com/docs/ProgrammingRuby/) is available online.