Eloquent Ruby Review

Front 1

Print all the words in docs.words

Back 1

docs.words.each { |word| puts word }

Front 2

Which format should Classes be in?

Back 2

CamelCased

Front 3

Which format should methods, arguments and variables be in?

Back 3

snake_cased

Front 4

Which format should constants be in?

Back 4

SNAKED_UPPERCASE

Front 5

What is a better way to write the following:

if not @read_only

Back 5

unless @read_only

Front 6

What is a better way to write the following:

while ! document_is_printed?

Back 6

until document.printed?

Front 7

One liner to conditionally set @title to new_title only if the document is not read only.

Back 7

@title = new_title unless @read_only

or

@title = new_title if @writable

Front 8

One liner to call document.print_next_page only if document is not printed or has pages available.

Back 8

document.print_next_page while document.pages_available?

or

document.print_next_page until document.printed?

Front 9

How does ruby treat bools?

Back 9

Only false or nil are treated as false. Everything else is true.

Front 10

What does a ternary operator look like in ruby?

Back 10

file = all ? 'specs' : 'latest_specs'

if all is true, 'specs' is returned

if all is false, 'latest_specs' is returned

Front 11

How would you initialize a variable only if the variable is nil?

Back 11

@first_name ||= ' '

Set the new value of @first_name to the old value of @first_name, unless that is nil, in which case set it to the empty string

Front 12

What should you avoid doing when using ||= to initialize things?

Back 12

Avoid initializing booleans

Front 13

What is a shortcut for creating an array of strings?

Back 13

poem_words = %w{ twinkle little star how I wonder }

Front 14

What is a shortcut for creating hashes?

Back 14

book_info = { first_name: 'Russ', last_name: 'Olsen' }

Front 15

How would you make a method that takes an arbitrary set of arguments?

Back 15

def some_method( *args* )

Front 16

How do multiple arguments get parsed when using a splat?

Back 16

They are passed in as an array

Front 17

What is the shortcut for passing a hash as an argument?

Back 17

load_font( :name => 'times roman', :size => 12)

or

load_font :name => 'times roman', :size => 12

Front 18

How would you use an each block to access data in a hash?

Back 18

movies.each { |name, value| puts "#{name} => #{value}" }

Front 19

How is .map different from .each?

Back 19

.map creates a new array containing everything that the block returns

It is useful for transforming the contents of a collection en masse

Front 20

What does .inject do?

Back 20

Every time it calls the block, it replaces the current result with the return value of the previous call to the block. It returns the result as its return value when it runs out of elements.

Front 21

How would you run a method in place on an object rather than returning a new object? (For many methods, not all)

Back 21

Add a bang to the method (Example: a.reverse! )