Refactor intro files

Author: Darius Neatu

intro-1.rb

@@ -1,10 +1,8 @@
-a = 10
-puts "a string\" #{a}"
-puts 'a string #{a}'
-p %{a string" " '' ''
-  foo
-  bar
-}
-%(a string)
+# base types
+p nil
+p true
+p false
+p 1
+p 0
 
-# => intro-2.rb
+# => intro-2.rb

intro-10.rb

@@ -0,0 +1,12 @@
+# even more ruby basics
+
+p "a string".capitalize # => "A string"
+
+p 1.to_s # => "1"
+
+p "foo".to_sym # => :foo
+
+p :foo.to_s # => "foo"
+
+# => test/even_more_basics_test.rb
+# => intro-11.rb

intro-2.rb

@@ -1,25 +1,27 @@
-1 # an integer
-# p 1.public_methods
+# Truthy and falsey in Ruby
 
-MOLOZ = 123
-p MOLOZ.to_s
-:foo # a symbol
-#foo
-p :foo.to_s
+if true
+  puts "true is truthy, duh!"
+else
+  puts "true is falsey, wtf!"
+end
 
-# Strings get allocated each time
-p "foo".object_id
-p "foo".object_id
-p "foo".object_id
+if false
+  puts "false is truthy, wtf!"
+else
+  puts "false is falsey, duh!"
+end
 
-# Symbols do not
-p :foo.object_id
-p :foo.object_id
-p :foo.object_id
+if nil
+  puts "nil is truthy"
+else
+  puts "nil is falsey"
+end
 
-p 1.to_s.to_sym.public_methods
+if 0
+  puts "0 is truthy"
+else
+  puts "0 is falsey"
+end
 
-p "123foo".to_i
-p "foo123".to_i
-
-# => intro-21.rb
+# => intro-3.rb

intro-3.rb

@@ -1,10 +1,12 @@
-"a string".capitalize # => "A string"
+a = 10
 
-1.to_s # => "1"
+puts "a string \" #{a} \""
+puts 'a string #{a}'
 
-"foo".to_sym # => :foo
+p %{a string" " '' ''
+  foo
+  bar
+}
+%(a string)
 
-:foo.to_s # => "foo"
-
-# => test/even_more_basics_test.rb
 # => intro-4.rb

intro-4.rb

@@ -1,22 +1,14 @@
-if true
-  p :hello
-else
-  p :no_hello
-end
+# Integers, symbols and strings
 
-p :hello if false
+1 # an integer
+# p 1.public_methods
 
-p :hello unless false
+MOLOZ = 123
+p MOLOZ.to_s
 
-bar = 10 if false
+:foo # a symbol
+#foo
+p :foo.to_s
+p "foo".to_sym
 
-p bar
-
-a = if true
-      10
-    else
-      11
-    end
-p a 
-
-# => methods.rb
+# => intro-5.rb

intro-5.rb

@@ -0,0 +1,16 @@
+# Strings get allocated each time
+p "foo".object_id
+p "foo".object_id
+p "foo".object_id
+
+# Symbols do not
+p :foo.object_id
+p :foo.object_id
+p :foo.object_id
+
+p 1.to_s.to_sym.public_methods
+
+p "123foo".to_i
+p "foo123".to_i
+
+# => intro-6.rb

intro-6.rb

@@ -0,0 +1,19 @@
+# arrays
+# http://ruby-doc.org/core-2.2.0/Array.html
+
+['an',  'array']
+[1, 2, 3, 4]
+p [1, 2, "foo",  :bar]
+
+#%w(an array)
+
+a = %w(foo bar baz) #=> shortcut for array of strings
+
+
+for value in a
+  puts value
+end
+
+
+# => test/basics_test.rb
+# => intro-7.rb

intro-7.rb

@@ -0,0 +1,23 @@
+# arrays - operations
+a = [1, 2, 3, 4, 5]
+b = [1, 2, 3, 10]
+
+p a + b
+p a - b
+p a & b
+p a | b
+p a.include?(1)
+p a.include?(10)
+
+a.push(10)
+p a
+a.pop
+p a
+
+a.unshift(10)
+p a
+p a.shift
+p a
+
+# => test/basics_test.rb
+# => intro-8.rb

intro-8.rb

@@ -0,0 +1,20 @@
+# Hash
+# http://ruby-doc.org/core-2.2.0/Hash.html
+
+a = { :foo => "bar" } # a hash
+
+a["foo"] = :bar
+a[1] = Fixnum
+a[Fixnum] = 1
+
+p 1.class
+
+p a.keys
+p a.values
+
+p "Pretty display:"
+for key, value in a
+  puts "#{key}(#{key.class}) -> #{value}"
+end
+
+# => intro-9.rb

intro-9.rb

@@ -0,0 +1,19 @@
+# Range
+# http://ruby-doc.org/core-2.2.0/Range.html
+
+p (1..10).include?(3) # range
+
+a = (1..3)
+
+for value in a
+  puts value
+end
+
+
+p (-1..-5).to_a      #=> []
+p (-5..-1).to_a      #=> [-5, -4, -3, -2, -1]
+p ('a'..'e').to_a    #=> ["a", "b", "c", "d", "e"]
+p ('a'...'e').to_a   #=> ["a", "b", "c", "d"]
+
+
+# => intro-10.rb