Thursday, October 18, 2007

Ruby Hashes: Good Programming Habit

When you're making a hash in Ruby, you can add a trailing comma with no problems.

E.g.:

>> h = {:x => :y,}
=> {:x=>:y}

The benefit here is that you can then add subsequent key-value pairs without ever getting those lame "oops I forgot a comma" errors.

8 comments:

  1. Works with lists, too:

    >> foo = [1,2,]
    => [1, 2]

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  2. Wha? I could have sworn I tried that at least once before and it didn't work. Good to know it does the right thing after all.

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  3. Rubinius and JRuby are both bleeding-edge; if they lack the implementation, that's something to add.

    @piers - it **doesn't** work without the curly braces. so if you use Ruby's "invisible curly braces" then you can't use this trick. but if you are using curly braces it's a good habit to be in.

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  4. Internet Explorer will hate you if you do the same with javascript.

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  5. Internet Explorer seems filled with hate. At the minimum, it's definitely grumpy.

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