is it possible to use hash keys as a first level variables inside ruby method?

Question

I'll try to explain myself a little bit more

# Lets say I have this hash
options = {a: 1, b: 2}

# and here I'm calling the method
some_method(options)

def some_method(options)
  # now instead of using options[:a] I'd like to simply use a.
  options.delete_nesting_and_create_vars
  a + b # :a + :b also good.

thanks!

Possible duplicate of [How to dynamically create a local variable?](http://stackoverflow.com/questions/18552891/how-to-dynamically-create-a-local-variable) — Wand Maker, Jan 27 '16 at 16:05

score 4 · Answer 1 · answered Jan 27 '16 at 15:55

4

Is it possible using Ruby2 splat parameters:

options = {a: 1, b: 2}

def some_method1(a:, b:)
  a + b
end

or:

def some_method2(**options)
  options[:a] + options[:b]
end


some_method1 **options
#⇒ 3
some_method2 **options
#⇒ 3

answered Jan 27 '16 at 15:55

Aleksei Matiushkin

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I have not seen usage like first example, can you please explain what is happening in that case, especially what does `a:` really mean in this case. – Wand Maker Jan 27 '16 at 16:04
@WandMaker these are simple hash-parameters, accepted since Ruby2, but without default values. You should’ve seen `def fun a: 42, b: nil` — that’s the same. – Aleksei Matiushkin Jan 27 '16 at 16:06
1

Thanks, got it now. Its called [keyword arguments](https://robots.thoughtbot.com/ruby-2-keyword-arguments) – Wand Maker Jan 27 '16 at 16:18
1

@WandMaker Indeed, I can’t memoize that name for unknown reason :) – Aleksei Matiushkin Jan 27 '16 at 16:21

score 2 · Accepted Answer · answered Jan 27 '16 at 15:55

2

If your options are fixed, like only :a and :b are the only keys, you can write the method like this:

def some_method(a:, b:)
  a + b
end

options = {a: 1, b: 2}

some_method(options) #=> 3

answered Jan 27 '16 at 15:55

Babar Al-Amin

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is it possible to use hash keys as a first level variables inside ruby method?

2 Answers2