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Ruby

Posted by Jiaming Zhang
Jiaming Zhang
10,170 Points

How can I convert string input to method call?

Assume I have a object called MyObject

class MyObject
  def foo
    # do something
  end

  def bar
    # do something else
  end
end

I want to create a function that take string as input. If the string equal to "foo", call the foo method, if the string equal to "bar", call the "foo" method, if the string equal neither, do nothing.

In Ruby, how can I achieve what I just describe?

1 Answer

Geoff Parsons
Geoff Parsons
11,667 Points

You can always use the send method. It accepts a symbol, so simply cast the argument to a symbol before calling it. This in combination with respond_to? may be what you're looking for.

  def do_something(action)
    action = action.to_sym
    if respond_to?(action)
      send(action)
    end
  end

Also depending on what you're looking to do with this sort of method you may want to look into the inner workings of method_missing.

Geoff Parsons
Geoff Parsons
11,667 Points

Actually the cast to a symbol isn't even necessary - send and respond_to? both accept strings.