如何将对象的字段转储到控制台?

时间:2008-12-09 22:55:24

标签: ruby printf-debugging

当我运行一个简单的Ruby脚本时,将对象的字段转储到控制台的最简单方法是什么?

我正在寻找类似于PHP print_r()的东西,它也适用于数组。

9 个答案:

答案 0 :(得分:375)

可能:

puts variable.inspect

答案 1 :(得分:51)

您可能会发现methods方法的用法,该方法返回对象的方法数组。它与print_r不同,但有时仍然有用。

>> "Hello".methods.sort
=> ["%", "*", "+", "<", "<<", "<=", "<=>", "==", "===", "=~", ">", ">=", "[]", "[]=", "__id__", "__send__", "all?", "any?", "between?", "capitalize", "capitalize!", "casecmp", "center", "chomp", "chomp!", "chop", "chop!", "class", "clone", "collect", "concat", "count", "crypt", "delete", "delete!", "detect", "display", "downcase", "downcase!", "dump", "dup", "each", "each_byte", "each_line", "each_with_index", "empty?", "entries", "eql?", "equal?", "extend", "find", "find_all", "freeze", "frozen?", "grep", "gsub", "gsub!", "hash", "hex", "id", "include?", "index", "inject", "insert", "inspect", "instance_eval", "instance_of?", "instance_variable_defined?", "instance_variable_get", "instance_variable_set", "instance_variables", "intern", "is_a?", "is_binary_data?", "is_complex_yaml?", "kind_of?", "length", "ljust", "lstrip", "lstrip!", "map", "match", "max", "member?", "method", "methods", "min", "next", "next!", "nil?", "object_id", "oct", "partition", "private_methods", "protected_methods", "public_methods", "reject", "replace", "respond_to?", "reverse", "reverse!", "rindex", "rjust", "rstrip", "rstrip!", "scan", "select", "send", "singleton_methods", "size", "slice", "slice!", "sort", "sort_by", "split", "squeeze", "squeeze!", "strip", "strip!", "sub", "sub!", "succ", "succ!", "sum", "swapcase", "swapcase!", "taguri", "taguri=", "taint", "tainted?", "to_a", "to_f", "to_i", "to_s", "to_str", "to_sym", "to_yaml", "to_yaml_properties", "to_yaml_style", "tr", "tr!", "tr_s", "tr_s!", "type", "unpack", "untaint", "upcase", "upcase!", "upto", "zip"]

答案 2 :(得分:47)

to_yaml方法似乎有时很有用:

$foo = {:name => "Clem", :age => 43}

puts $foo.to_yaml

返回

--- 
:age: 43
:name: Clem

(这是否取决于正在加载的某些YAML模块?或者通常是否可用?)

答案 3 :(得分:28)

p object

Ruby doc for p.

  

p(*args) public

     

对于每个对象,直接写入obj.inspect   通过程序标准输出的换行符。

答案 4 :(得分:14)

如果您只是在对象中查找实例变量,这可能很有用:

obj.instance_variables.map do |var|
  puts [var, obj.instance_variable_get(var)].join(":")
end

或作为复制和粘贴的一行代码:

obj.instance_variables.map{|var| puts [var, obj.instance_variable_get(var)].join(":")}

答案 5 :(得分:10)

put foo.to_json

可能会派上用场,因为默认加载了json模块

答案 6 :(得分:5)

如果您要打印已经缩进的JSON

require 'json'
...
puts JSON.pretty_generate(JSON.parse(object.to_json))

答案 7 :(得分:3)

我遇到了这个帖子,因为我正在寻找类似的东西。我喜欢这些回复,他们给了我一些想法,所以我测试了.to_hash方法,并且也非常适合用例。 soo:

object.to_hash

答案 8 :(得分:-1)

object.attributes_name

=&GT; [“id”,“name”,“email”,“created_at”,“updated_at”,“password_digest”,“remember_token”,“admin”,“marketing_permissions”,“terms_and_conditions”,“禁用”,“black_list”,“ zero_cost“,”password_reset_token“,”password_reset_sent_at“]

object.attributes.values

=&GT; [1,“tom”,“tom @ tom.com”,星期二,2015年6月2日00:16:03 UTC +00:00,星期二,02六月2015 00:22:35 UTC +00:00,“$ 2a $ 10 $ gUTr3lpHzXvCDhVvizo8Gu / MxiTrazOWmOQqJXMW8gFLvwDftF9Lm“,”2dd1829c9fb3af2a36a970acda0efe5c1d471199“,true,nil,nil,nil,nil,nil,nil,nil]