How to add a new value to a string by pattern?

Question

ruby

There is a line: It is necessary to turn it into the following: How to do this optimally? Did it like this:
my_str = "a, b, c, d, e"

my_str = "'%a%', '%b%', '%c%', '%d%', '%e%'"

a = a
  .split(', ')
  .map{ |e| e = "'%"+e+"%'" }
  .join(', ')

Answer 1

str.gsub(/\w+/, '\'%\0%\'')