Question

我正在使用一个循环，在每次迭代期间更改哈希值。然后我尝试在每次迭代结束时将新的哈希值推送（添加）到数组中。

# Array and hash to hold response
response = []
test_data = Hash.new    

# Array of search elements for loop
search = ["testOne", "testTwo", "testThree"]    

current_iteration = 0   

# Loop through search words and get data for each
search.each do |element| 

    test_data["Current element"] = element
    test_data["Current iteration"] = current_iteration

    response.push(test_data)
    current_iteration += 1
end

似乎数组只保存最后一次迭代的哈希值。关于这个的任何提示？

Answer 1

是的，这是因为Hash对象始终包含唯一键，并且键包含最新的更新值。现在，在each方法中，对于通过数组"Current element"的每次迭代，您都会继续更新与"Current iteration"和search相同的键。如上所述，哈希中的键始终保存最新的更新值，因此您的哈希值也保留最后一个迭代值。

现在，您正在数组hash内推送相同的response对象，因此最终您在数组response内获得了相同的3个哈希值。您希望实现的目标，以满足您需要使用Object#dup。

更正后的代码：

response = []
test_data = hash.new    

# array of search elements for loop
search = ["testone", "testtwo", "testthree"]    

current_iteration = 0   

# loop through search words and get data for each
search.each do |element| 

    test_data["current element"] = element
    test_data["current iteration"] = current_iteration

    response.push(test_data.dup)
    current_iteration += 1
end

response 
# => [{"current element"=>"testone", "current iteration"=>0},
#     {"current element"=>"testtwo", "current iteration"=>1},
#     {"current element"=>"testthree", "current iteration"=>2}]

这样做的优雅方式：

search = ["testone", "testtwo", "testthree"]    

response = search.map.with_index do |element,index|
  {"current element" => element, "current iteration" => index}
end

response 
# => [{"current element"=>"testone", "current iteration"=>0},
#     {"current element"=>"testtwo", "current iteration"=>1},
#     {"current element"=>"testthree", "current iteration"=>2}]

循环中的哈希数组，在每次迭代期间重写哈希值

1 个答案: