How to list local-variables in Ruby?

Question

def method
  a = 3
  b = 4

  some_method_that_gives # [a, b] 
end

Saad

Answer 1

local_variables

It outputs array of symbols, presenting variables. In your case: [:a, :b]

Jitterbug

Can't believe I didn't find it before. Thanks! – Saad

Some versions of Ruby output an array of strings instead of an array of symbols. Ruby 2.0 and 1.9 use symbols, but Ruby 1.8.7 used strings. – Weeden

Answer 2

local_variables lists local variables but it lists them before they are defined. See this:

p local_variables
a = 1
p local_variables

this outputs

[:a]
[:a]

which may not be what you expect. Contrast with defined?

p defined? a
a = 1
p defined? a

which outputs the more anticipated

nil
"local-variable"

Sparrowgrass

Answer 3

if you're looking for the list with their values:

variables = self.local_variables.each_with_object({}) { |key, hash| hash[key] = binding.local_variable_get(key) }

Allelomorph

To avoid using eval you can use Binding#local_variable_get instead. I modified you solution like this: local_variables.each_with_object({}) { |key, hash| hash[key] = binding.local_variable_get(key) } – Lento