Ruby编程之哈希函数介绍和数组合并与拼接

h1 = {
  'room1'=>'The Treasure Room',
  'room2'=>'The Throne Room',
  'loc1'=>'A Forest Glade',
  'loc2'=>'A Mountain Stream'
}

h2 = {1=>'one', 2=>'two', 3=> 'three'}
h1['room1'] = 'You have wandered into a dark room'
h1.delete('loc2')
p(h1)
#=> {"room1"=>"You have wandered into a dark room",
#=> "room2"=>"The Throne Room",
#=> "loc1"=>"A Forest Glade"}
p(h1.has_key?('loc2')) #=> false
p(h2.has_value?("two")) #=>true
p(h2.invert) #=> {"one"=>1, "two"=>2, "three"=>3}
p(h2.keys) #=>[1, 2, 3]
p(h2.values) #=>["one", "two", "three"]
p(h2.key("two")) # use this Ruby 1.9

{"room1"=>"You have wandered into a dark room", "room2"=>"The Throne Room", "loc1"=>"A Forest Glade"}
false
true
{"one"=>1, "two"=>2, "three"=>3}
[1, 2, 3]
["one", "two", "three"]
2

h1 = {'key1'=>'val1', 'key2'=>'val2', 'key3'=>'val3', 'key4'=>'val4'}
h2 = {'key1'=>'val1', 'KEY_TWO'=>'val2', 'key3'=>'VALUE_3', 'key4'=>'val4'}
p( h1.keys & h2.keys ) # set intersection (keys)
#=> ["key1", "key3", "key4"]
p( h1.values & h2.values ) # set intersection (values)
#=> ["val1", "val2", "val4"]
p( h1.keys+h2.keys ) # concatenation
#=> [ "key1", "key2", "key3", "key4", "key1", "key3", "key4", "KEY_TWO"]
p( h1.values-h2.values ) # difference
#=> ["val3"]
p( (h1.keys << h2.keys) ) # append
#=> ["key1", "key2", "key3", "key4", ["key1", "key3", "key4", "KEY_TWO"]]
p( (h1.keys << h2.keys).flatten.reverse ) # 'un-nest' arrays and reverse
#=> ["KEY_TWO", "key4", "key3", "key1", "key4", "key3", "key2", "key1"]

["key1", "key3", "key4"]
["val1", "val2", "val4"]
["key1", "key2", "key3", "key4", "key1", "KEY_TWO", "key3", "key4"]
["val3"]
["key1", "key2", "key3", "key4", ["key1", "KEY_TWO", "key3", "key4"]]
["key4", "key3", "KEY_TWO", "key1", "key4", "key3", "key2", "key1"]

a =[1,2,3]
b =[4,5,6]
c = a + b #=> c=[1, 2, 3, 4, 5, 6] a=[1, 2, 3]
a << b #=> a=[1, 2, 3, [4, 5, 6]]
p(c)
p(a)

[1, 2, 3, 4, 5, 6]
[1, 2, 3, [4, 5, 6]]

a=[1, 2, 3, [4, 5, 6]]
p(a.flatten) #=> [1, 2, 3, 4, 5, 6]

[1, 2, 3, 4, 5, 6]

开发环境:Rubymine

The book of Ruby----A hands-on guide for the Adventurous---[美]Huw Collingbourne---no starch press