A common set of problems to learn new languages

问题:

With "Polyglot" programming techniques becoming more relevant, it is almost a necessity to use the "right" PL for the problem. However, learning new languages takes time which usually most project team can't afford. What is the best way to learn a new programming language? Is there a common set of problems that can be solved to reach a certain level of competence?

回答1:

Well, it depends what you want to do. (web, db, whatever).

Generally I'd want to know:

• What's the library like, how do I reference it
• What ORMs are there
• What build/deployment platforms exist for it
• How does it handle updates
• How do I do general things, like:
  • DB Access
  • File things
  • Display UI's

and so on.

回答2:

Really, learning is only by doing -- you need a project that you can use the given language for.

Project Euler is the first thing to come to mind as an oft-used set of problems to try in a new language, even if it's not something I've ever tried.

If the language is another JVM or CLR hosted one, the issues about learning the environment can be set aside -- you can use all your familiar APIs in your Clojure/Scala/F#... code -- and concentrate on the syntax and idiom.

Otherwise, you're probably using the new language because it has a good fit for the particular problem you want to solve (e.g. native code and functional -> Haskell; distributed and concurrent -> Erlang) so the fit of the feature set is known in advance but you have the extra load of learning the standard APIs. And that's what prototyping is for.

回答3:

The book Programming Challenges and the associated website provide a large list of algorithmic problems, with automatic online judging in several languages (Java, C, C++). Any algorithm textbook can give you lots of examples of basic data structures and procedures to try and implement, which is often a nice way to get some practice with basic language syntax and features. My personal favourite for this is The Algorithm Design Manual, which is language agnostic, but there are plenty of good language-specific books available as well (Mastering Algorithms in Perl or Data Structures and Algorithms in Java, for example).

If you're interested in a general set of mathematical problems to try and solve, Project Euler is a great resource.

For more day to day problems, I find the cookbook approach most helpful. For example, both Perl and Python have excellent O'Reilly cookbooks, as well as online resources, which provide short examples of many common and important problems. As mentioned in another answer, the key here is to find canonical examples of basic features you will need, particularly by leveraging what's available in standard libraries. I usually try and build up my own small library of examples as I go along, e.g. a socket example, a DB access example, a file reading example, a simple numerical solver, etc, which I then pillage for ideas when it's time to write production code.