Question

我是Ruby的新手，我正在努力注入＆＃39; Ruby中现有哈希的键/值对。我知道你可以用＆lt;＆lt;对于阵列，例如

arr1 = []
a << "hello"

但我可以为哈希做类似的事情吗？像

这样的东西

hash1 = {}
hash1 << {"a" => 1, "b" => 2}

基本上，我在基于条件的循环中尝试推送键值对。

# Encoder: This shifts each letter forward by 4 letters and stores it  in a hash called cipher. On reaching the end, it loops back to the first letter
def encoder (shift_by)
alphabet = []
cipher = {}
alphabet =  ("a".."z").to_a
alphabet.each_index do |x|
        if (x+shift_by) <= 25
            cipher = {alphabet[x] => alphabet[x+shift_by]}
        else
            cipher = {alphabet[x] => alphabet[x-(26-shift_by)]} #Need this piece to push additional key value pairs to the already existing cipher hash.
        end
end

很抱歉在这里粘贴我的整个方法。有人可以帮我这个吗？

Answer 1

有三种方式：

.merge(other_hash)返回包含other_hash内容和hsh内容的新哈希。

hash = { a: 1 }
puts hash.merge({ b: 2, c: 3 }) # => {:a=>1, :b=>2, :c=>3}

.merge!(other_hash)将other_hash的内容添加到hsh。

hash = { a: 1 }
puts hash.merge!({ b: 2, c: 3 }) # => {:a=>1, :b=>2, :c=>3}

最有效的方法是修改现有哈希，直接设置新值：

hash = { a: 1 }
hash[:b] = 2
hash[:c] = 3
puts hash # => {:a=>1, :b=>2, :c=>3}

这些方法的相应基准：

       user     system      total        real
   0.010000   0.000000   0.010000 (  0.013348)
   0.010000   0.000000   0.010000 (  0.003285)
   0.000000   0.000000   0.000000 (  0.000918)

Answer 2

你可以merge!两个哈希：

hash1 = {}
hash1.merge!({"a" => 1, "b" => 2})

如何将键值对附加到Ruby中的现有哈希？

2 个答案: