Question

This code from my developer below… does it expect something like “1 – January” and try to parse it into something else?

I changed the code on my form so now the value being passed to this controller is just “1” instead of “1 – January”

How can I fix this so I don’t get the “can’t convert nil into string” error?

  def get_expiry_month_number(monty_det, expiry_year)
    if MONTH_NAMES.include? monty_det
       month_number = MONTH_NAMES.index(monty_det)
       month_number = MONTH_NUMBERS[month_number]
       expiry_year = month_number.to_s + expiry_year[expiry_year.length-3..expiry_year.length-1]
       return expiry_year
    end
  end

Answer 1

In your example you are running into the problem that one of your strings in your calculation for year is nil. Most likely this one,

expiry_year[expiry_year.length-3..expiry_year.length-1]

You can try and fix this by calling to_s on the culprit variable, thus converting the nil into '' and then concatenated.

Like so: expiry_year = month_number.to_s + expiry_year[expiry_year.length-3..expiry_year.length-1].to_s

However, this may have other seen consequences and isn’t recommended. A better approach would be to find out why something you expect is a string is turning out to be empty, and perhaps displaying an appropriate error.

Could you explain a little bit more about what the function is supposed to do? And perhaps the value of expiry_year and monty_det when the error occurs? puts statements can be a big help here.