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Editorial Team
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Asked: 2026-05-26T04:22:41+00:00

I am just beginning to learn Ruby and have the following code in a

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I am just beginning to learn Ruby and have the following code in a project:

USER_ATTRS = [:login, :password, :lastname, :firstname, :mail, :admin]

What does this do? Where do :login and all the other things come from?

Are they just properties of a class (user, probably)?

Can someone can help me out please? Because I can’t really find this on the net.

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1 Answer

  1. Editorial Team

    The short answer is:

    “The ‘:’ indicates a Ruby symbol’

    The medium length answer would add:

    Symbols are immutable objects that differ from strings in important ways.

    The Real Answer:
    You will have to learn Ruby to learn Rails. I also labored under the impression that I could just pick-up Rails and leave Ruby as just one more language under my belt. I was wrong. Ruby is different. I could point out how it is interpreted and makes use of open classes, but this isn’t the real reason you too will have trouble “learning as you do’ with Ruby and Rails. Ruby allows for a kind of syntactical overloading that some call ‘syntactic sugar’ It is one way to make Ruby code shorter and more readable. It will also hinder your ability to simply infer functionality from the code you see. You will see many well conceived Rails examples that leave you puzzled and eventually frustrated. These examples will look terse and mysterious and you may wonder, “Why don’t they just make it more intuitive?” The answer is many will also look at those same examples and say, “That’s good Ruby.” They have their reasons.

    The Remedy:
    Read. http://www.manning.com/black2/ and and http://pragprog.com/book/ppmetr/metaprogramming-ruby This rails book http://pragprog.com/book/rails4/agile-web-development-with-rails and these guides http://guides.rubyonrails.org/ then took me where I needed to go.

    What makes this point best? If you haven’t yet, work through this outstanding tutorial http://ruby.railstutorial.org/ruby-on-rails-tutorial-book It is one of the best programming tutorials I have ever read. It covers Rails very well and says some things about Ruby. Yet, it fails. If it is the only source you work from, you will not know enough Ruby to progress to the point where you can generate your own code.

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