Ruby - Revision history

Suhridk: /* Code blocks */

2014-09-06T11:21:45Z

Code blocks

2014-09-06T11:11:38Z

Collections, blocks, iterators

2014-09-06T11:08:37Z

Collections, blocks, iterators

2014-09-06T11:04:05Z

Collections, blocks, iterators

2014-09-06T10:57:16Z

Collections, blocks, iterators

2014-09-06T10:55:33Z

Collections, blocks, iterators

2014-09-06T10:53:59Z

Collections, blocks, iterators

2014-09-06T10:53:13Z

Expressions and control-structures

2014-09-06T10:44:49Z

Expressions and control-structures

2014-09-06T10:43:20Z

Strings, Regex, Symbols

@@ Line 187: / Line 187: @@
 * A block consists of multiple lines of code, enclosed in {}, that can be passed to a method.
 * A block may only appear in the source if it is adjacent to the method call.
 <syntaxhighlight lang="ruby">
@@ Line 197: / Line 198: @@
 three_times {puts "Hello World"}
 </syntaxhighlight>

@@ Line 181: / Line 181: @@
 city = {"blr" => {:state => "KA"}, "mas" => {:state => "TN"}}
 city["blr"][:state] #prints KA
 </syntaxhighlight>

← Older revision		Revision as of 11:08, 6 September 2014
Line 174:		Line 174:
	phone.key(1) # Returns home		phone.key(1) # Returns home

		+	</syntaxhighlight>
		+
		+	* Multidimensional collections : nest one collection inside another
		+
		+	<syntaxhighlight lang="ruby">
		+	city = {"blr" => {:state => "KA"}, "mas" => {:state => "TN"}}
		+	city["blr"][:state] #prints KA
	</syntaxhighlight>		</syntaxhighlight>

← Older revision		Revision as of 10:57, 6 September 2014
Line 162:		Line 162:

	a[1..2] #returns a sub array		a[1..2] #returns a sub array
		+
		+	</syntaxhighlight>
		+
		+	* Hashes : associative array for array its an int, hash key is any object.
		+
		+	<syntaxhighlight lang="ruby">
		+
		+	phone = {:home => 1, :work => 2, :mobile => 3}

	</syntaxhighlight>		</syntaxhighlight>

@@ Line 152: / Line 152: @@
 * Array, Hash, Set collections.
 * The collection classes include Enumerable module as a mixin, they share a common set of methods provided by enumerable which provides iterator methods.
+* Array can also be treated as a stack, push, pop etc.
 <syntaxhighlight lang="ruby">
@@ Line 160: / Line 160: @@
 a = [33, "hello", 2.2] //Non homogeneous array
 </syntaxhighlight>

@@ Line 158: / Line 158: @@
   @post = Post.all #post variable is an Array
 end
 </syntaxhighlight>

← Older revision		Revision as of 10:53, 6 September 2014
Line 147:		Line 147:
	* for/in loop iterates over an enumerable collection. for var in collection do body end		* for/in loop iterates over an enumerable collection. for var in collection do body end
	* while condition do body end, until condition do body end.		* while condition do body end, until condition do body end.
		+
		+	= Collections, blocks, iterators =
		+
		+	* Array, Hash, Set collections.
		+	* The collection classes include Enumerable module as a mixin, they share a common set of methods provided by enumerable which provides iterator methods.
		+
		+	<syntaxhighlight lang="ruby">
		+
		+	def index
		+	@post = Post.all #post variable is an Array
		+	end
		+
		+	</syntaxhighlight>

@@ Line 145: / Line 145: @@
 * ==, !=, =~ (regx), !~ (not regex)  === (case equality)
 * Oppposite of if exists : until <expr> code end, executes code until expr is true (other than false/nil)
+* for/in loop iterates over an enumerable collection. for var in collection do body end
+* while condition do body end, until condition do body end.

← Older revision		Revision as of 10:43, 6 September 2014
Line 136:		Line 136:
	* So they offer a space advantage.		* So they offer a space advantage.
	* Use case : if the identity of the object is important, use a symbol.		* Use case : if the identity of the object is important, use a symbol.
		+
		+	= Expressions and control-structures =
		+
		+	* Ruby syntax is expression oriented - everything is an expression and therefore evaluates to something.
		+	* Control structures which are traditionally statements are treated as expressions in Ruby. (The value they assume is the last expr they evaluated)
		+	* Conditionals if expr code end. No curly braces. Also elsif available.
		+	* Shorthand : code if <expr>
		+	* ==, !=, =~ (regx), !~ (not regex) === (case equality)
		+	* Oppposite of if exists : until <expr> code end, executes code until expr is true (other than false/nil)
		+
		+
		+
		+	*