[英]How do I get the keys of a hash whose values equal to given arguments in ruby?
因此,我正在尝试从Rubeque http://www.rubeque.com/problems/related-keys-of-hash/中解决此问题。 基本上我只需要获取一个哈希值的键,其值等于给定的参数,我想知道你们是否可以给我一些提示? 解决这个问题,非常感谢
这就是我到目前为止
class Hash
def keys_of(*args)
key = Array.new
args.each { |x| key << x}
key.each { |x,y| x if y == key}
end
end
assert_equal [:a], {a: 1, b: 2, c: 3}.keys_of(1)
assert_equal [:a, :d], {a: 1, b: 2, c: 3, d: 1}.keys_of(1)
assert_equal [:a, :b, :d], {a: 1, b: 2, c: 3, d: 1}.keys_of(1, 2)
使用Hash#select :
{a: 1, b: 2, c: 3, d: 1}.select { |key, value| value == 1 }
# => {:a=>1, :d=>1}
{a: 1, b: 2, c: 3, d: 1}.select { |key, value| value == 1 }.keys
# => [:a, :d]
{a: 1, b: 2, c: 3, d: 1}.select { |key, value| [1,2].include? value }.keys
#=> [:a, :b, :d]
class Hash
def keys_of(*args)
select { |key, value| args.include? value }.keys
end
end
h = {a: 1, b: 2, c: 3, d: 1}
p h.each_with_object([]){|(k,v),ar| ar<<k if [1,2].member?(v)}
# >> [:a, :b, :d]
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