Question

I’m trying to initialize a variable as a float and then add to it in a times loop. Here’s my code:

amt = 0.0

5.times do
  amt = amt + ("%.2f" % (item.price * 0.05)) 
end

Here’s the error:

String can't be coerced into Float

EDIT:

I’ve changed the 1.times do. I had adapted my code so that it would be more readable, the 1.times wasn’t in my actual code.

Answer 1

Firstly, try not to use floats for money – what you’ll need to do in this case is use BigDecimal – floating point math is not accurate.

To use BigDecimal, require ‘bigdecimal’ in your application.rb

Then, what you want is:

amt = BigDecimal.new("0")

1.times do
  price = BigDecimal.new(item.price.to_s)
  factor = BigDecimal.new("0.05")
  amt += (price * factor).round(2)
end

amt