# create a mapping of state to abbreviation
states = {
'Oregon' => 'OR',
'Florida' => 'FL',
'California' => 'CA',
'New York' => 'NY',
'Michigan' => 'MI'
}
# create a basic set of states and some cities in them
cities = {
'CA' => 'San Francisco',
'MI' => 'Detroit',
'FL' => 'Jacksonville'
}
# add some more cities
cities['NY'] = 'New York'
cities['OR'] = 'Portland'
# puts out some cities
puts '-' * 10
puts "NY State has: #{cities['NY']}"
puts "OR State has: #{cities['OR']}"
# puts some states
puts '-' * 10
puts "Michigan's abbreviation is: #{states['Michigan']}"
puts "Florida's abbreviation is: #{states['Florida']}"
# do it by using the state then cities dict
puts '-' * 10
puts "Michigan has: #{cities[states['Michigan']]}"
puts "Florida has: #{cities[states['Florida']]}"
# puts every state abbreviation
puts '-' * 10
states.each do |state, abbrev|
puts "#{state} is abbreviated #{abbrev}"
end
# puts every city in state
puts '-' * 10
cities.each do |abbrev, city|
puts "#{abbrev} has the city #{city}"
end
# now do both at the same time
puts '-' * 10
states.each do |state, abbrev|
city = cities[abbrev]
puts "#{state} is abbreviated #{abbrev} and has city #{city}"
end
puts '-' * 10
# by default ruby says "nil" when something isn't in there
state = states['Texas']
if !state
puts "Sorry, no Texas."
end
# default values using ||= with the nil result
city = cities['TX']
city ||= 'Does Not Exist'
puts "The city for the state 'TX' is: #{city}"创建函数
module Dict
def Dict.new(num_buckets=256)
#Initializes a Dict with the given number of buckets.
aDict = []
(0...num_buckets).each do |i|
aDict.push([])
end
return aDict
end
def Dict.hash_key(aDict, key)
# Given a key this will create a number and then convert it to
# an index for the aDict's buckets.
return key.hash % aDict.length
end
def Dict.get_bucket(aDict, key)
#Given a key, find the bucket where it would go
bucket_id = Dict.hash_key(aDict, key)
return aDict[bucket_id]
end
def Dict.get_slot(aDict, key, default=nil)
# Returns the index, key, and value of a slot found in a bucket.
bucket = Dict.get_bucket(aDict, key)
bucket.each_with_index do |kv, i|
k, v = kv
if key == k
return i, k, v
end
end
return -1, key, default
end
def Dict.get(aDict, key, default=nil)
# Gets the value in a bucket for the given key, or the default.
i, k, v = Dict.get_slot(aDict, key, default=default)
return v
end
def Dict.set(aDict, key, value)
# Sets the key to the value, replacing any existing value.
bucket = Dict.get_bucket(aDict, key)
i, k, v = Dict.get_slot(aDict, key)
if i >= 0
bucket[i] = [key, value]
else
bucket.push([key, value])
end
end
def Dict.delete(aDict, key)
# Deletes the given key from the Dict.
bucket = Dict.get_bucket(aDict, key)
(0...bucket.length).each do |i|
k, v = bucket[i]
if key == k
bucket.delete_at(i)
break
end
end
end
def Dict.list(aDict)
# Prints out what's in the Dict.
aDict.each do |bucket|
if bucket
bucket.each {|k, v| puts k, v}
end
end
end
end修改后
require './dict.rb'
# create a mapping of state to abbreviation
states = Dict.new()
Dict.set(states, 'Oregon', 'OR')
Dict.set(states, 'Florida', 'FL')
Dict.set(states, 'California', 'CA')
Dict.set(states, 'New York', 'NY')
Dict.set(states, 'Michigan', 'MI')
# create a basic set of states and some cities in them
cities = Dict.new()
Dict.set(cities, 'CA', 'San Francisco')
Dict.set(cities, 'MI', 'Detroit')
Dict.set(cities, 'FL', 'Jacksonville')
# add some more cities
Dict.set(cities, 'NY', 'New York')
Dict.set(cities, 'OR', 'Portland')
# puts out some cities
puts '-' * 10
puts "NY State has: #{Dict.get(cities, 'NY')}"
puts "OR State has: #{Dict.get(cities, 'OR')}"
# puts some states
puts '-' * 10
puts "Michigan's abbreviation is: #{Dict.get(states, 'Michigan')}"
puts "Florida's abbreviation is: #{Dict.get(states, 'Florida')}"
# do it by using the state then cities dict
puts '-' * 10
puts "Michigan has: #{Dict.get(cities, Dict.get(states, 'Michigan'))}"
puts "Florida has: #{Dict.get(cities, Dict.get(states, 'Florida'))}"
# puts every state abbreviation
puts '-' * 10
Dict.list(states)
# puts every city in state
puts '-' * 10
Dict.list(cities)
puts '-' * 10
# by default ruby says "nil" when something isn't in there
state = Dict.get(states, 'Texas')
if !state
puts "Sorry, no Texas."
end
# default values using ||= with the nil result
city = Dict.get(cities, 'TX', 'Does Not Exist')
puts "The city for the state 'TX' is: #{city}"