元素替换 - Ruby

Question

我正在尝试创建一个新数组，其中原始数组的元素被替换为它们在散列中的对应值。我想将 arr 中的每个元素与哈希中的键进行比较，如果它们相等，则将它们铲入 arr 并在最后 return 。为什么我的代码不起作用，我如何 access/return 散列中各个条目的键值，而不仅仅是键指向的值？如果你明白我在说什么。

def element_replace(arr, hash)
  count = []
    
  
  for i in arr do
    if i == hash.key
     count << value
    else 
      count << i 
    end
  end
   
  return count

end

arr1 = ["LeBron James", "Lionel Messi", "Serena Williams"]
hash1 = {"Serena Williams"=>"tennis", "LeBron James"=>"basketball"}
print element_replace(arr1, hash1) # => ["basketball", "Lionel Messi", "tennis"]
puts

arr2 = ["dog", "cat", "mouse"]
hash2 = {"dog"=>"bork", "cat"=>"meow", "duck"=>"quack"}
print element_replace(arr2, hash2) # => ["bork", "meow", "mouse"]
puts

Answer 1

Ruby 的 Hash::fetch 将是一种获得所需结果的技巧：

> players = ["LeBron James", "Lionel Messi", "Serena Williams"]
=> ["LeBron James", "Lionel Messi", "Serena Williams"]
> sports_data = {"Serena Williams"=>"tennis", "LeBron James"=>"basketball"}
=> {"Serena Williams"=>"tennis", "LeBron James"=>"basketball"}
> players.map { |player| sports_data.fetch(player, player) }
=> ["basketball", "Lionel Messi", "tennis"]

Answer 2

您可以 map 数组来散列键或保留数组元素本身：如果缺少键 (return nil) 保留数组元素：

arr1.map { |k| hash1[k] || k }
#=> ["basketball", "Lionel Messi", "tennis"]

Answer 3

如果默认情况下您的散列应该 return 密钥，您可以使用 default_proc:

hash = { 'Serena Williams' => 'tennis', 'LeBron James' => 'basketball' }
hash.default_proc = proc { |hash, key| key }

这给你：

hash['LeBron James'] #=> "basketball"    # explicit value
hash['Lionel Messi'] #=> "Lionel Messi"  # default value

或者，使用数组：

arr = ['LeBron James', 'Lionel Messi', 'Serena Williams']

hash.values_at(*arr)
#=> ["basketball", "Lionel Messi", "tennis"]

Answer 4

def element_replace(arr, hash)
  new_arr = []
  arr.each { |n|
   if hash.has_key?(n) 
     new_arr << hash[n]
   else 
     new_arr << n 
     
   end 

  }

  
  return new_arr
 end 







arr1 = ["LeBron James", "Lionel Messi", "Serena Williams"]
hash1 = {"Serena Williams"=>"tennis", "LeBron James"=>"basketball"}
print element_replace(arr1, hash1) # => ["basketball", "Lionel Messi", "tennis"]
puts

arr2 = ["dog", "cat", "mouse"]
hash2 = {"dog"=>"bork", "cat"=>"meow", "duck"=>"quack"}
print element_replace(arr2, hash2) # => ["bork", "meow", "mouse"]
puts

元素替换 - Ruby

Element Replace - Ruby

ruby

arrays

string

dictionary

hashtable