Question

我有以下代码：

@referred_emails = Array.new
@referred_emails = params.select{|k, v| k.start_with?('referred_') }.values

puts "referred emails array: " + @referred_emails.inspect.to_s

@referred_emails.each_with_index do |referred_email, index|
    puts "index is #{index}.  referred_email is #{referred_email}"
end

这是服务日志：

15:25:34 web.1  | referred emails array: ["theiremail1", "theiremail2", "theiremail3"]
15:25:34 web.1  | index is 0.  referred_email is theiremail1
15:25:35 web.1  | index is 1.  referred_email is theiremail3

如您所见，由于某种原因，数据库中的第二个元素被跳过。它应该输出以下内容：

15:25:34 web.1  | referred emails array: ["theiremail1", "theiremail2", "theiremail3"]
15:25:34 web.1  | index is 0.  referred_email is theiremail1
15:25:34 web.1  | index is 1.  referred_email is theiremail2
15:25:35 web.1  | index is 2.  referred_email is theiremail3

但由于某种原因，它一直在跳过第二个。

以下是参数：

15:25:34 web.1  |   Parameters: {"utf8"=>"✓", 
    "authenticity_token"=>"f7f0idqcQpXG/XzhQYCaEj3xQHLiQz1Nf1z9gF3CMxM=", 
    "referrer_email"=>"", "referrer_name"=>"", "referred_0"=>"theiremail1", 
    "referred_1"=>"theiremail2", "referred_2"=>"theiremail3", "commit"=>"SUBMIT"}

为什么跳过第二个元素？

Answer 1

不确定最终会出现什么问题但是，一切似乎至少对我有用：

params = {"referrer_email"=>"", "referrer_name"=>"", "referred_0"=>"theiremail1", "referred_1"=>"theiremail2", "referred_2"=>"theiremail3"}
params.select{|k, v| k.include?('referred_') }.values
#=> ["theiremail1", "theiremail2", "theiremail3"]

或：

params.select{|k, v| k.start_with?('referred_') }.values
#=> ["theiremail1", "theiremail2", "theiremail3"]

或：

params.select{|k, v| k.include?('referred_') }.
       each_with_index{|(k, v), i| puts "index is #{i}. referred_email is #{v}" } 
#=> index is 0. referred_email is theiremail1
#=> index is 1. referred_email is theiremail2
#=> index is 2. referred_email is theiremail3

Answer 2

您提供的代码绝对没有错。如果我将以下输出粘贴到名为test.rb的空白文件中：

params = {
  "utf8"=>"✓", 
  "authenticity_token"=>"f7f0idqcQpXG/XzhQYCaEj3xQHLiQz1Nf1z9gF3CMxM=", 
  "referrer_email"=>"",
  "referrer_name"=>"",
  "referred_0"=>"theiremail1", 
  "referred_1"=>"theiremail2",
  "referred_2"=>"theiremail3",
  "commit"=>"SUBMIT"
}

@referred_emails = Array.new
@referred_emails = params.select{|k, v| k.start_with?('referred_') }.values

puts "referred emails array: " + @referred_emails.inspect.to_s

@referred_emails.each_with_index do |referred_email, index|
    puts "index is #{index}.  referred_email is #{referred_email}"
end

...然后我运行ruby test.rb，我在Ruby 2.0 +上得到以下输出：

referred emails array: ["theiremail1", "theiremail2", "theiremail3"]
index is 0.  referred_email is theiremail1
index is 1.  referred_email is theiremail2
index is 2.  referred_email is theiremail3

如果您的代码中存在错误，则不在您提供的代码示例中。

rails .each无缘无故地跳过第二个元素

2 个答案: