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? — Wand Maker
– Wand Maker, Commented Jan 27, 2016 at 16:05

Aleksei Matiushkin · Accepted Answer · 2016-01-27 15:55:28Z

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, 2016 at 15:55

Aleksei Matiushkin

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4 Comments

Wand Maker Over a year ago

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.

Aleksei Matiushkin Over a year ago

@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.

Wand Maker Over a year ago

Thanks, got it now. Its called keyword arguments

Aleksei Matiushkin Over a year ago

@WandMaker Indeed, I can’t memoize that name for unknown reason :)

Babar Al-Amin · Accepted Answer · 2016-01-27 15:55:29Z

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, 2016 at 15:55

Babar Al-Amin

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