Ruby学习过程中积累下来的测试代码-优快云博客

本文深入探讨了Ruby编程语言的基础知识，包括基础语法、变量作用域、块和闭包、标准类型、网络编程等内容，并通过实例展示了如何使用Ruby进行实际操作。

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基础部分：

puts -1943.abs

def say_goodnight(name)
  yield
  puts "Good night, " + name
end
say_goodnight("Shen Bin") { puts "Hi " }


$greeting = "Hello"
@name = "Shen Bin 1"
puts "#$greeting, #@name"


a = [1, 'cat', 3.14]
puts a[-1]
a = [1, 3, 5, 7, 9]
puts a[1, 3]
puts a[1..3]
puts a[1...3]


person1 = "Shen Yan"
person2 = person1
person1[0] = "C"
puts person2
person3 = person1.dup
person1[0] = "S"
puts person3


class File
  def File.open_and_process(*args)
    result = f = File.open(*args)
    if block_given?
      result = yield f
      f.close()
    end
    return result
  end
end
File.open_and_process("D:/rails.txt", "r") do |file|
  while line = file.gets
    puts line
  end
end


['cat', 'dog', 'horse'].each { |name| print name, " "}
["H", 'A', "B"].collect { |x| x.succ }
a = ['3 4', '5 6', '7 8']
a.each do |line|
  v1, v2 = line.split
#  print v1 + v2, " "
  print Integer(v1) + Integer(v2), " "
end
a = %w{ ant bee cat dog elk }
puts a[1]


b = Hash.new(0)  # Hash.new 0
b['key1'] += 1;
puts b['key1']


a = %w{ ant bee cat dog elk }
a.each { |a| puts a if a =~ /\w{2}t/ }
puts '-------------------------'
puts a.grep(/\w{2}t/)

类，对象：

class Song
  attr_reader :artist, :duration
  attr_writer :artist
  attr_accessor :name
  
  def initialize(name, artist, duration)
    @name = name
    @artist = artist
    @duration = duration
  end
  
  def to_s
    "Song: #@name -- #@artist (#@duration)"
  end
  
  def duration=(new_duration)
    @duration = new_duration
  end
end
song = Song.new('a', 'b', 100)
#puts song.inspect
puts song.to_s

song.name = 'c'
song.artist = 'd'
song.duration = 600
puts song.to_s
puts song.name + " | " + song.artist + " | " + String(song.duration)

类变量：

class Song
  @@plays = 0
  def initialize(name, artist, duration)
    @name = name
    @artist = artist
    @duration = duration
    @plays = 0
  end
  
  def play
    @plays += 1
    @@plays += 1
    puts "This song: #@plays plays. Total #@@plays plays."
  end
end
s1 = Song.new('Song1', "Artist1", 234)
s2 = Song.new('Song2', "Artist2", 345)
s1.play
s1.play
s2.play
s1.play

Block，闭包

def fibonacci_up_to(max)
  x, y = 1, 1
  while x < max
    if(block_given?) 
      yield x
    end
    x, y = y, x+y
  end
end
fibonacci_up_to(1000) { |f| print f, " "}


def n_times(thing)
  return lambda { |n| thing * n }
end
p1 = n_times(23)
puts p1.call(3)
puts p1.call(4)
p2 = n_times('Hello ')
puts p2.call(2)

each和collect的区别 --- 返回值不同

a = [1, 2, 3]
b = a.each { |i| i*2 }
puts b
c = a.collect { |i| i*2 }
puts c

标准类型：数字/字符串/区间等

a = 123_456_789
puts a
puts a.class

b = "Now is #{
  def the(a)
    'The ' + a
  end
  the('time')
} for all good coders..."
puts b

c = %q/generate single-quoted string/
d = %Q!generate double-quoted string!
e = %Q{Secounds/Day: #{24*60*60}}
puts c,d,e

f = <<HERE_DOCUMENT_STRING
  Hello, Shen Bin.
  We are using Ruby.
HERE_DOCUMENT_STRING
puts f

g = (0 .. 10).to_a
h = ('bar' .. 'bat').to_a
puts g, h

i = (0 .. 10) === 5
j = (0 .. 10) === 15
k = ('a' .. 'j') === 'c'
l = ('a' .. 'j') === 'o'
puts i, j, k, l

如果方法定义的最后一个参数的前缀为&，那么所关联的block会被转换为一个Proc对象，然后赋值给这个参数

class TaxCalculator
  def initialize(name, &block)
    @name, @block = name, block
  end
  def get_tax(amount)
    "#@name on #{amount} = #{ @block.call(amount) }"
  end
end
tc = TaxCalculator.new("Sales Tax") { |amt| amt * 0.075 }
puts tc.get_tax(100)
puts tc.get_tax(250)

使用lambda表达式抽取block

print "(t)imes or (p)lus"
t = gets
print "number: "
m = gets.to_i
if t =~ /^t/
  puts ((1..10).collect { |n| n * m }.join(", "))
else
  puts ((1..10).collect { |n| n + m }.join(", "))
end

#使用lambda表达式把block抽取出来

print "(t)imes or (p)lus"
t = gets
print "number: "
m = gets.to_i
if t =~ /^t/
  calc = lambda { |n| n * m }
else
  calc = lambda { |n| n + m }
end
puts ((1..10).collect(&calc).join(", "))

If / case when等表达式也可以有返回值：

a = gets
b = if a.to_i > 0
  1
elsif a.to_i == 0
  0
else
  -1
end
puts b

覆盖已有方法

class Fixnum
  alias plus +
  def +(other)
    plus(other).succ
  end
end
puts 1+1
a = 3
puts a += 4
puts a+a+a

反引号`以及%x --- 将被操作系统当做命令来执行

puts `dir`
puts %x{ echo 'Hello World'! }

在Ruby1.8以后，赋值语句的值总是参数的值而方法的返回值将被丢掉

class Test
  def val=(val)
    @val = val
    return 99
  end
end
t = Test.new
a = t.val = 2
puts a

self的作用（区别）

class BrokenApmlifier
  attr_accessor :left, :right
  def volume=(vol)
#    @left = @right = vol
    left = self.right = vol
  end
end
ba = BrokenApmlifier.new
ba.left = ba.right = 3
ba.volume = 5
puts ba.left
puts ba.right

并行赋值：

x = 0
a, b, c = x, x+=1, x+=1
print a, ' ', b, ' ', c

#交换两个变量的值
a, b = b, a

a = [1, 2, 3, 4]
b, c = a            # b == 1, c == 2
b, *c = a           # b == 1, c == [2, 3, 4]
b, c = 99, a        # b == 99, c == [1, 2, 3, 4]
b, *c = 99, a       # b == 99, c == [[1, 2, 3, 4]]
b, c = 99, *a       # b == 99, c == 1
b, *c = 99, *a      # b == 99, c == [1, 2, 3, 4

嵌套赋值

b, (c, d), e = 1, 2, 3, 4               # b == 1, c == 2, d == nil, e == 3
b, (c, d), e = [1, 2, 3, 4]             # b == 1, c == 2, d == nil, e == 3
b, (c, d), e = 1, [2, 3], 4             # b == 1, c == 2, d == 3, e == 4
b, (c, d), e = 1, [2, 3, 4], 5          # b == 1, c == 2, d == 3, e == 5
b, (c, *d), e = 1, [2, 3, 4], 5         # b == 1, c == 2, d == [3, 4], e == 5

#注意，Ruby不支持C或Java中自增(++)和自减(--)运算，需要使用(+=)或(-=)代替。

变量作用域：

x = y = nil # 此处不定义的话程序会抛错
[1, 2, 3].each do |a|
  x = a
  y = x + 1
end
puts x, y

网络编程：

require 'net/http'
h = Net::HTTP.new('www.yahoo.com', 80)
response = h.get('/')
if response.message == 'OK'
  puts response.body.scan(/<img src=".*?"/m).uniq
end

动态创建：

5.times do |i|
  File.open('temp.rb', "w") do |f|
    f.puts "module Temp"
    f.puts " def Temp.var"
    f.puts "    #{i}"
    f.puts " end"
    f.puts "end"
  end
  load "temp.rb"
  puts Temp.var
end