&& (and)
|| (or)
! (not)
!= ==
>= <=
true false
3 != 4 && !("testing" != "test" || "Ruby" == "Ruby")
people = 20
cats = 30
dogs = 15
if people < cats
puts "Too many cats! The world is doomed!"
end
if people > cats
puts "Not many cats! The world is saved!"
end
if people < dogs
puts "The world is drooled on!"
end
if people > dogs
puts "The world is dry!"
end
dogs += 5
if people >= dogs
puts "People are greater than or equal to dogs."
end
if people <= dogs
puts "People are less than or equal to dogs."
end
if people == dogs
puts "People are dogs."
end
people = 30
cars = 40
trucks = 15
if cars > people
puts "We should take the cars."
elsif cars < people
puts "We should not take the cars."
else
puts "We can't decide."
end
if trucks > cars
puts "That's too many trucks."
elsif trucks < cars
puts "Maybe we could take the trucks."
else
puts "We still can't decide."
end
if people > trucks
puts "Alright, let's just take the trucks."
else
puts "Fine, let's stay home then."
end
一个简单的对话游戏
puts "You enter a dark room with two doors. Do you go through door #1 or door #2?"
print "> "
door = $stdin.gets.chomp
if door == "1"
puts "There's a giant bear here eating a cheese cake. What do you do?"
puts "1. Take the cake."
puts "2. Scream at the bear."
print "> "
bear = $stdin.gets.chomp
if bear == "1"
puts "The bear eats your face off. Good job!"
elsif bear == "2"
puts "The bear eats your legs off. Good job!"
else
puts "Well, doing %s is probably better. Bear runs away." % bear
end
elsif door == "2"
puts "You stare into the endless abyss at Cthulhu's retina."
puts "1. Blueberries."
puts "2. Yellow jacket clothespins."
puts "3. Understanding revolvers yelling melodies."
print "> "
insanity = $stdin.gets.chomp
if insanity == "1" || insanity == "2"
puts "Your body survives powered by a mind of jello. Good job!"
else
puts "The insanity rots your eyes into a pool of muck. Good job!"
end
else
puts "You stumble around and fall on a knife and die. Good job!"
end
数组（array）：包含了一些有序对象的容器
hairs = ['brown', 'blond', 'red']
eyes = ['brown', 'blue', 'green']
weights = [1, 2, 3, 4]
the_count = [1, 2, 3, 4, 5]
fruits = ['apples', 'oranges', 'pears', 'apricots']
change = [1, 'pennies', 2, 'dimes', 3, 'quarters']
# this first kind of for-loop goes through a list
# in a more traditional style found in other languages
for number in the_count
puts "This is count #{number}"
end
# same as above, but in a more Ruby style
# this and the next one are the preferred
# way Ruby for-loops are written
fruits.each do |fruit|
puts "A fruit of type: #{fruit}"
end
# also we can go through mixed lists too
# note this is yet another style, exactly like above
# but a different syntax (way to write it).
change.each {|i| puts "I got #{i}" }
# we can also build lists, first start with an empty one
elements = []
# then use the range operator to do 0 to 5 counts
(0..5).each do |i|
puts "adding #{i} to the list."
# pushes the i variable on the *end* of the list
elements.push(i)
end
# now we can print them out too
elements.each {|i| puts "Element was: #{i}" }
i = 0
numbers = []
while i < 6
puts "At the top i is #{i}"
numbers.push(i)
i += 1
puts "Numbers now: ", numbers
puts "At the bottom i is #{i}"
end
puts "The numbers: "
# remember you can write this 2 other ways?
numbers.each {|num| puts num }
animals = ['bear', 'tiger', 'penguin', 'zebra']
bear = animals[0]
数组中的第一个元素是从0开始（Long Story...）
def gold_room
puts "This room is full of gold. How much do you take?"
print "> "
choice = $stdin.gets.chomp
# this line has a bug, so fix it
if choice.include?("0") || choice.include?("1")
how_much = choice.to_i
else
dead("Man, learn to type a number.")
end
if how_much < 50
puts "Nice, you're not greedy, you win!"
exit(0)
else
dead("You greedy bastard!")
end
end
def bear_room
puts "There is a bear here."
puts "The bear has a bunch of honey."
puts "The fat bear is in front of another door."
puts "How are you going to move the bear?"
bear_moved = false
while true
print "> "
choice = $stdin.gets.chomp
if choice == "take honey"
dead("The bear looks at you then slaps your face off.")
elsif choice == "taunt bear" && !bear_moved
puts "The bear has moved from the door. You can go through it now."
bear_moved = true
elsif choice == "taunt bear" && bear_moved
dead("The bear gets pissed off and chews your leg off.")
elsif choice == "open door" && bear_moved
gold_room
else
puts "I got no idea what that means."
end
end
end
def cthulhu_room
puts "Here you see the great evil Cthulhu."
puts "He, it, whatever stares at you and you go insane."
puts "Do you flee for your life or eat your head?"
print "> "
choice = $stdin.gets.chomp
if choice.include? "flee"
start
elsif choice.include? "head"
dead("Well that was tasty!")
else
cthulhu_room
end
end
def dead(why)
puts why, "Good job!"
exit(0)
end
def start
puts "You are in a dark room."
puts "There is a door to your right and left."
puts "Which one do you take?"
print "> "
choice = $stdin.gets.chomp
if choice == "left"
bear_room
elsif choice == "right"
cthulhu_room
else
dead("You stumble around the room until you starve.")
end
end
start
while true / =~ / exit(0)