How do I print out the contents of an object in Rails for easy debugging

Question

I think I m trying to get the PHP equivalent of print r    print human-readable   at present the raw output is   ActiveRecord  Relation 0x10355d1c0   What should I do

User · Accepted Answer

I generally first try  inspect  if that doesn t give me what I want  I ll switch to  to yaml   class User   attr accessor  name   age end  user   User new user name    John Smith  user age   30  puts user inspect    gt    lt User 0x423270c  name  John Smith    age 30 gt  puts user to yaml    gt  ---  ruby object User    gt  age  30    gt  name  John Smith   Hope that helps

User · Answer

inspect is what you re looking for  it s way easier IMO than  to yaml   user   User new user name    will  user email    will example com   user inspect   lt name   will   email   will example com  gt

User · Answer

inspect is great but sometimes not good enough  E g  BigDecimal prints like this    lt BigDecimal 7ff49f5478b0  0 1E2  9 18  gt    To have full control over what s printed you could redefine to s or inspect methods  Or create your own one to not confuse future devs too much     class Something  lt  ApplicationRecord      def to s       attributes map   k  v    k   gt  v to s     inject  merge      end    end   This will apply a method  i e  to s  to all attributes  This example will get rid of the ugly BigDecimals   You can also redefine a handful of attributes only     def to s     attributes merge   my attribute  my attribute to s      end   You can also create a mix of the two or somehow add associations

User · Answer

define the to s method in your model  For example  class Person  lt  ActiveRecord  Base   def to s      Name   self name  Age   self age  Weight    self weight     end end   Then when you go to print it with  puts it will display that string with those variables

User · Answer

pp does the job too  no gem requiring is required    a   Accrual first   pp  a    lt Accrual 0x007ff521e5ba50  id  4   year  2018   Jan    lt BigDecimal 7ff521e58f08  0 11E2  9 27  gt    Feb    lt BigDecimal 7ff521e585d0  0 88E2  9 27  gt    Mar    lt BigDecimal 7ff521e58030  0 0  9 27  gt    Apr    lt BigDecimal 7ff521e53698  0 88E2  9 27  gt    May    lt BigDecimal 7ff521e52fb8  0 8E1  9 27  gt    June    lt BigDecimal 7ff521e52900  0 8E1  9 27  gt    July    lt BigDecimal 7ff521e51ff0  0 8E1  9 27  gt    Aug    lt BigDecimal 7ff521e51bb8  0 88E2  9 27  gt    Sep    lt BigDecimal 7ff521e512f8  0 88E2  9 27  gt    Oct    lt BigDecimal 7ff521e506c8  0 0  9 27  gt    Nov    lt BigDecimal 7ff521e43d38  0 888E3  9 27  gt    Dec    lt BigDecimal 7ff521e43478  0 0  9 27  gt     You can also print two instances of an object    pp  Accrual first   Accrual second

User · Answer

In Rails you can print the result in the View by using the debug  Helper ActionView  Helpers  DebugHelper   app view controllers post controller rb def index   posts   Post all end   app view posts index html erb  lt    debug  posts    gt    start your server rails -s   results  in browser   -  ruby object Post   raw attributes      id  2     title  My Second Post     body  Welcome   This is another example post     published at   2015-10-19 23 00 43 469520      created at   2015-10-20 00 00 43 470739      updated at   2015-10-20 00 00 43 470739    attributes   ruby object ActiveRecord  AttributeSet     attributes   ruby object ActiveRecord  LazyAttributeHash       types   amp 5         id   amp 2  ruby object ActiveRecord  Type  Integer           precision             scale             limit             range   ruby range             begin  -2147483648             end  2147483648             excl  true         title   amp 3  ruby object ActiveRecord  Type  String           precision             scale             limit           body   amp 4  ruby object ActiveRecord  Type  Text           precision             scale             limit           published at   ruby object ActiveRecord  AttributeMethods  TimeZoneConversion  TimeZoneConverter           subtype   amp 1  ruby object ActiveRecord  Type  DateTime             precision               scale               limit           created at   ruby object ActiveRecord  AttributeMethods  TimeZoneConversion  TimeZoneConverter           subtype   1         updated at   ruby object ActiveRecord  AttributeMethods  TimeZoneConversion  TimeZoneConverter           subtype   1

User · Answer

I m using the awesome print gem  So you just have to type    ap  var

User · Answer

You need to use debug  var   It s exactly like  print r

[ruby-on-rails] How do I print out the contents of an object in Rails for easy debugging?

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