按键数组设置红宝石哈希元素值 [英] set ruby hash element value by array of keys

问题描述

这里是我得到的：

  hash = {：a => {：b => [{：c => old_val}]}} 
 keys = [：a，：b，0，：c] 
 new_val = 10 
  

散列结构和密钥集可以不同。

i需要获得

  hash [：a] [：b] [0] [：c] == new_val 
  

谢谢！

/Enumerable.html#method-i-injectrel =noreferrer> 注入 来遍历嵌套结构：

  hash = {：a => {：b => [{：c => foo}]}} 
 keys = [：a，：b，0，：c] 
 
 keys.inject（hash）{| structure，key |结构[key]} 
＃=> foo
  

所以，你只需要修改它就可以对最后一个键进行设置。也许像

  last_key = keys.pop 
＃=> ：c 
 
 nested_hash = keys.inject（hash）{| structure，key |结构[key]} 
＃=> {：c => foo} 
 
 nested_hash [last_key] =bar
 
 hash 
＃=> {：a => {：b => [{：c => bar}]}} 
  

here is what i got:

hash = {:a => {:b => [{:c => old_val}]}}
keys = [:a, :b, 0, :c]
new_val = 10

hash structure and set of keys can vary.
i need to get

hash[:a][:b][0][:c] == new_val

Thanks!

解决方案

You can use inject to traverse your nested structures:

hash = {:a => {:b => [{:c => "foo"}]}}
keys = [:a, :b, 0, :c]

keys.inject(hash) {|structure, key| structure[key]}
# => "foo"

So, you just need to modify this to do a set on the last key. Perhaps something like

last_key = keys.pop
# => :c

nested_hash = keys.inject(hash) {|structure, key| structure[key]}
# => {:c => "foo"}

nested_hash[last_key] = "bar"

hash
# => {:a => {:b => [{:c => "bar"}]}}

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