dwilbank questions

• Replace multiple periods in string with just one period
• converting a c++ formula into javascript
• determine if array is arithmetic or geometric progression (from Coderbyte)
• Rails / Devise: undefined method `router_name' for nil:NilClass - what is coming through as nil?
• what kind of syntax is on the right side of this equation?
• Mutually recursive functions - exercise not making sense to me
• Shortcut to make case/switch return a value
• Unfamiliar use of square brackets in calling a function
• Why is my RSpec not loading Devise::Test::ControllerHelpers?

dwilbank answers