From 73071f605991f4b3870845d702be536b540fcf34 Mon Sep 17 00:00:00 2001
From: jbranchaud <jbranchaud@gmail.com>
Date: Fri, 24 Apr 2015 08:41:04 -0500
Subject: [PATCH] Add Destructuring Arrays In Blocks as a ruby til.

---
 README.md                              |  1 +
 ruby/destructuring-arrays-in-blocks.md | 38 ++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 ruby/destructuring-arrays-in-blocks.md

diff --git a/README.md b/README.md
index bbab1bb..76674d8 100644
--- a/README.md
+++ b/README.md
@@ -49,6 +49,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 
 - [Are They All True?](ruby/are-they-all-true.md)
 - [Create an Array of Stringed Numbers](ruby/create-an-array-of-stringed-numbers.md)
+- [Destructuring Arrays In Blocks](ruby/destructuring-arrays-in-blocks.md)
 - [Limit Split](ruby/limit-split.md)
 - [Parallel Bundle Install](ruby/parallel-bundle-install.md)
 - [Summing Collections](ruby/summing-collections.md)
diff --git a/ruby/destructuring-arrays-in-blocks.md b/ruby/destructuring-arrays-in-blocks.md
new file mode 100644
index 0000000..9f564c1
--- /dev/null
+++ b/ruby/destructuring-arrays-in-blocks.md
@@ -0,0 +1,38 @@
+# Destructuring Arrays In Blocks
+
+If I am iterating over a collection of arrays (let's say tuples) and I want
+to access the values of those arrays within the iteration block, I may do
+something like the following:
+
+```ruby
+> a = [[1,2],[3,4],[5,6]]
+> a.each { |tuple| puts "#{tuple[0]} - #{tuple[1]}" }
+1 - 2
+3 - 4
+5 - 6
+```
+
+I can, however, use array destructuring which will not only simplify the
+code, but also make it more readable, explicit, and intentional.
+
+```ruby
+> a = [[1,2],[3,4],[5,6]]
+> a.each { |x_coord,y_coord| puts "#{x_coord} - #{y_coord}" }
+1 - 2
+3 - 4
+5 - 6
+```
+
+In the same way, I can destructure arrays that are part of a hash like so:
+
+```ruby
+> h = {one: [1,2], two: [3,4], three: [5,6]}
+> h.each { |key, (x_coord, y_coord)| puts "#{x_coord} - #{y_coord}" }
+1 - 2
+3 - 4
+5 - 6
+```
+
+Note the parentheses that are placed around the part that is being
+destructured. Without these parentheses, ruby will interpret `x_coord` as
+the whole array value and `y_coord` will be `nil`.