React Hooks: useState with Arrays

I spent a good portion of the work day today trying to code up a simple form to accept a list of zip codes and put them in an array. The final form looks as follows: As you can see there are a few zip codes and then we can click the ‘Add Zip Code’…

Ruby on Rails intersections of multiple arrays

finding the intersection in Ruby of 2 arrays is quite easy. If a is an array and b is an array then c can be the intersection as follows: c = a & b Similarly the union of the arrays can be found as follows: c = a | b The problem I had was…