ruby学习之Hash

一、定义：

hsh=Hash.new

hsh=Hash[1=>”a”,2=>”b”]

hsh={“1”=>”a”,2=>”b”}

支持任意对象为key，习惯使用Symbol

二、常用方法

#!/usr/bin/ruby
def printResult(args)
    print args
    puts ""
end
hsh={:a=>"hello",:b=>"world"}
puts hsh
# hsh.clear()
# puts hsh
hsh.delete(:a)
puts hsh
hsh[:c]="third"
puts hsh
hsh.delete_if(){|key,value| value=="third"}
puts hsh
puts hsh.has_key?(:b)
puts hsh.has_value?("world")
puts hsh.invert()
hsh[:d]="ddd"
hsh[:e]="eee"
printResult hsh.keys()
printResult hsh.values
printResult hsh.values_at(:b,:d)
puts hsh.length()
puts hsh.merge({:b=>"bbbb",:f=>"ffff"})
puts hsh.replace({:b=>"b2b2b2",:g=>"ggg"})
print hsh.to_a()

result:

{:a=>"hello", :b=>"world"}

{:b=>"world"}

{:b=>"world", :c=>"third"}

{:b=>"world"}

true

true

{"world"=>:b}

[:b, :d, :e]

["world", "ddd", "eee"]

["world", "ddd"]

3

{:b=>"bbbb", :d=>"ddd", :e=>"eee", :f=>"ffff"}

{:b=>"b2b2b2", :g=>"ggg"}

[[:b, "b2b2b2"], [:g, "ggg"]][Finished in 0.1s]

三、查找和迭代

Hash是可枚举类型的对象，具有其搜索遍历和排序的能力，参见ruby之Enumerable

#!/usr/bin/ruby
def printResult(args)
    print args
    puts ""
end
hsh={:a=>1,:b=>2,:c=>5,:d=>4}
printResult hsh.find_all(){|key,value| value > 2}
printResult hsh.map { |key,value| key }
printResult hsh.max
printResult hsh.sort
printResult hsh.sort_by(){|key,value| value}
hsh.each do |key,value|
    print key
end
puts ""
hsh.each_key() do |key|
    print key
end
puts ""
hsh.each_value() do |value|
    print value
end

result：

[[:c, 5], [:d, 4]]

[:a, :b, :c, :d]

[:d, 4]

[[:a, 1], [:b, 2], [:c, 5], [:d, 4]]

[[:a, 1], [:b, 2], [:d, 4], [:c, 5]]

abcd

abcd

1254

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