A Humanist's Introduction to Programming

(with Ruby)

  

Wayne Graham & Joe GilbertMITH, Oct. 19, 2010

What does that mean?

(We're still figuring it out.)

Why teach programming to humanities scholars?

Jean Bauer

Early American Foreign Service Database

Mapping Taqwacore: the Kominas

Why program?

• Express complex logic or relationships• Perform computations• Do things that take a long time or are difficult for humans to do (counting, comparing, repeating, graphing)

Why program?  "when you don't create things,   you become defined by your    tastes rather than ability. your   tastes only narrow & exclude   people. so create."    why the lucky stiff (@_why)

What is a programming language?

• An artificial language with a limited purpose

• A means of expressing computations (math) and algorithms (logic) 

What is a programming language?..like human languages in some ways!

• Syntax (form)

• Semantics (meaning)o signs/words (variables, symbols, numbers, strings)

o expressionso narrative ("flow," decisions, conditions, loops)o complex entities (methods, structures, & objects)

Why Ruby?

• General purpose• Object-oriented• Usable locally or over the web• English-like syntax and useful built-in features• "Fun" to write

Other commonly used languages: C, C++, Java, PHP, Python, JavaScript, ActionScript

 

"...trying to make Ruby natural, not simple." Yukihiro Matsumoto aka "Matz"

Why not Ruby?

• Not as easy to run on the web as PHP (or JavaScript)

• Used less often than PHP, and major platforms (WordPress, Drupal, Omeka) use PHP

• Ruby isn't Rails

• Object-oriented languages are conceptually difficult to grasp

What we will cover

• What kinds of information do we use in programs?

• How can we store and reuse information?

• How can we describe collections of information?

• What operations can we perform with information?

• How can we repeat steps?

• What if we only want to do things under certain conditions?

What we won't cover

• Building a database driven website

• Design patterns

• Testing code

• Inheritance

• Software design

• Modules

• Mixins

• Procs

• Lambdas

• Coercion (Monkey Patching)

Try it out!

irb 

http://www.ruby-lang.org/

http://tryruby.org/

http://rubyinstaller.org/

We work with a few basic types of information

Numbers like 1, 4000, -33.3

Text, including characters, words, sentences, and paragraphs

Types of informationnumbers, letters, boolean values

integers:4, 1040, -55, 9999

floating-point numbers:1.1, 0.444, 9999.0001, -3.33

text (strings):"a", 'cat', "The quick brown fox jumped over the lazy dogs.", '8 keys', '7’

boolean (yes or no?):true, false

Variables"words" that hold information

 > the_lonliest_number = 1=> 1 > truth = "beauty"=> "beauty"

Collections

Collectionstext, numbers...collections? Array:> presidents = ["Jefferson", "Madison", "Monroe"]=> ["Jefferson", "Madison", "Monroe"] presidents[0] = "Jefferson", presidents[1] = "Madison", etc. Associative array ("hash"): 

> states = {"VA" => "Virginia", "MD" => "Maryland"}=> {"VA" => "Virginia", "MD" => "Maryland"}

states["VA"] = "Virginia", states["MD"] = "Maryland"

Operatorsarithmetic and moremy_variable = 5my_other_variable = "hi" > my_variable + 2 => 7 > my_variable * 3=> 15 > my_other_variable + " there!"=> "hi there!" > presidents = presidents + ["Washington"]=> ["Jefferson", "Madison", "Monroe", "Washington"] > presidents = presidents - ["Washington"]=> ["Jefferson", "Madison", "Washington"]

What happens with presidents * 2?

Type castingduck typing and type casting

• Quotes are meaningful > my_favorite_number = '2'=> "2" > my_favorite_number + 2TypeError: can't convert Fixnum into String > my_favorite_number.to_i + 2=> 4

Special Symbols math operators

+ addition (and concatenation)- subtraction/ division* multiplication

assignment operators 

= assign a value 

+= add, then assign a value 

other operatorsequivalence, non-equivalence, boolean (and, or, etc.)

Printing things to the screen

puts "Doctor Who" puts tardis puts doctors[0]

puts doctors["David Tennant"] puts "My favorite episode is " + best_episode

Do something!

Store your street address, city, state, and zip code in variables (or even better, a hash!), then print them in the usual format:

Joseph Gilbert160 McCormick RoadCharlottesville, VA 22902

address = {'name' => 'Joseph Gilbert', 'street' => '160 McCormick Road', 'city' => 'Charlottesville', 'state' => 'VA', 'zip' => '22902'}puts address['name']puts address['street']puts address['city'] + ', ' + address['state'] + ' ' + address['zip']

Repeating yourself 

> puts presidents[0]Jefferson=>nil

> puts presidents[1]Madison=> nil

> puts presidents[2]Monroe=> nil

this isn't fun or efficient!

Repetition: "iterating" with each

> presidents.each do |president| > puts president> endJeffersonMadisonMonroe=> ["Jefferson", "Madison", "Monroe"]

.eachfor hashes

states = {"VA" => "Virginia", "MD" => "Maryland"}

states.each do |code, state| puts code.to_s + " is the postal code for " + state.to_send

Do Something, pt. 2

Create a collection of these authors and the year they passed away; print the collection in the following format:

Charles Dickens passed away in 1870.

Charles Dickens, 1870William Thackeray, 1863Anthony Trollope, 1882Gerard Manley Hopkins, 1889

authors = {"Charles Dickens" => "1870", "William Thackeray" => "1863", "Anthony Trollope" => "1882", "Gerard Manley Hopkins" => "1889"}

authors.each do |author, year|  puts author.to_s + " passed away in " + year.to_send

Resources• Learn to Program

http://pine.fm/LearnToProgram/

• Why's Poignant Guide to Rubyhttp://mislav.uniqpath.com/poignant-guide/

• Ruby Documentationhttp://ruby-doc.org/core/

• “Pick-axe Book” http://ruby-doc.org/docs/ProgrammingRuby/ 

• Teach Me to Codehttp://www.teachmetocode.com

• RubyTu.be

• Rubylearning.com