How long will it take a coder to learn ruby? [closed]_问答_开发者

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How long will it take for a developer to learn ruby. And develop a production website like stackove开发者_开发问答rflow ? Normally. If the developer have .NET experience but no ruby and MYSQL or PostgreSQL experience.

I worked with .net for about 3-4 years, and java for 3 years before that, now I work at a rails shop.

Learning basic syntax is dead simple. Wrapping your head around some of the concepts will take a lot longer. As a bit of a checklist

how instance variables work and are set (very different then c#)
how everything related to methods is just sugar for message passing
what self means at any given part of your code (especially self in class declaration scope vs method declaration scope)
mixins
when to use a module, when to use a class
how classes are just a different kind of object

This is the simple stuff. After that, you want to be learning more of this stuff

learning about the more commonly used language level callbacks (like method_missing and included)
wrapping your head around methods that define methods
understanding blocks, coroutines, procs, and how they all work together (this is probably number one)
understanding how method parsing works, and choosing the right amount of () or {} that will result in the least typing
wrapping your head around object individuation (this took a while for me)
stop using objects for everything, and stick to hashes where appropriate
learn when meta-programming is appropriate, and when it isn't (many, many rubyists out there do not know this well)
learning how to solve common problems with these new tools in better ways then is possible with something like C# (Builders, Adapters, and Strategies stand out to me as the most radically different in terms of GoF patterns)

It is hard to say how long this will take. For me, the first bits took about a month of playing with ruby and reading books. The second half probably took more like three or four (although there was rails learning in there too)

As for MySQL/pg, its not like you have to start completely from scratch. The tooling isn't as great as SSMS (imo, the best part of the MS stack), but it is enough to get by. If you use rails, most of the database stuff is abstracted away. If you need to check out something in the db, nine times out of ten you fire up a script/console and just use the ActiveRecord api (which is out of this world amazing)

EDIT:

Object Individuation means that each object instance is its own "thing", which is based on a class, but may not just be that class. here are some examples

first, we build a class

irb(main):001:0> class TestClass
irb(main):002:1> def tc
irb(main):003:2> puts 'testclass method'
irb(main):004:2> end
irb(main):005:1> end
=> nil

now we instantiate it twice

irb(main):006:0> t1 = TestClass.new
=> #<TestClass:0x7fea78ee6f78>
irb(main):007:0> t2 = TestClass.new
=> #<TestClass:0x7fea78ed6ba0>

def a method that is only on t2

irb(main):008:0> def t2.only_on_t2
irb(main):009:1> puts 'this will not be accessible anywhere else'
irb(main):010:1> end
=> nil
irb(main):011:0> t1.only_on_t2
NoMethodError: undefined method `only_on_t2' for #<TestClass:0x7fea78ee6f78>
    from (irb):11
    from :0
irb(main):012:0> t2.only_on_t2
this will not be accessible anywhere else
=> nil

redefine a method that is pulled in from the class, but only on t1

irb(main):013:0> def t1.tc
irb(main):014:1> puts 'redeffing something picked up from the class'
irb(main):015:1> end
=> nil
irb(main):016:0> t1.tc
redeffing something picked up from the class
=> nil
irb(main):017:0> t2.tc
testclass method
=> nil

The above code is extremely rare to see, because having a bunch of method definition stuff inline in another method is generally pretty ugly. Mixing in modules with specific instances is pretty powerful though, especially when you take duck typing into account.

irb(main):018:0> module TestModule
irb(main):019:1> def tm
irb(main):020:2> puts 'this is where it gets interesting'
irb(main):021:2> end
irb(main):022:1> end
=> nil
irb(main):023:0> t2.extend TestModule
=> #<TestClass:0x7fea78ed6ba0>
irb(main):024:0> t2.tm
this is where it gets interesting
=> nil
irb(main):025:0> t1.tm
NoMethodError: undefined method `tm' for #<TestClass:0x7fea78ee6f78>
    from (irb):25
    from :0
irb(main):026:0> t1.is_a? TestModule
=> false
irb(main):027:0> t2.is_a? TestModule
=> true

This is more advanced stuff, and is one of those things that is the last thing you should be reaching for, but there are cases where doing an on the fly extend is a much more elegant solution to a problem then the alternatives (which is a common warning with most advanced ruby stuff, don't do it this way because you can, only do it when you need to)

This is a massively subjective question, as it depends on your experience and time put into it. However, I recently learned Ruby, and was able to pick up the basics over a few days of reading the Pickaxe book. I would recommend that book if you have prior programming experience, or _why's Poignant Guide to Ruby if you have never programmed before.

So, you should be able to know some basic syntax after a few hours of work, but it will take you a lot longer to be proficient with the language. Expect a few months of solid learning to be able to call yourself advanced.

Since you mentioned web development, frameworks like Sinatra are pretty easy to get started with. Rails is a bit harder, and requires more learning before a functional website could be built. So, after having learned Ruby itself, I would say about 2 to 3 weeks (depending on time invested) to be able to build 'proper' websites with Sinatra. As for something like StackOverflow, that would take a lot longer, and probably a team of developers.

If you follow the "Ruby Koans", you will learn a great deal about Ruby in about 4 hours. After that, you have the practice, and it will come.

It is not a hard language to learn, especially if you are already familiar with languages that mix functional and object oriented concepts (like C#). It is a very expressive language, and lets you do more than C# when you get into meta-programming.

As for developing websites with Ruby, the defacto framework is Rails, which a site like StackOverflow can certainly be written. This comes with its own, steeper (IMO) learning curve. Rails does abstract the database away from you, so knowing a lot about the particular databases is not a necessity.