I read through that description and I was mentally gearing up to implement this. Then, you spin the wheel to randomly select based on these weights. The roulette-style selection process means that you create a giant roulette wheel with all of the candidates on it, and the size of each candidate’s wedge depends on their “fitness” score: how much of the desired result they have in them. Assume you’ve got a group of candidates in a breeding process. Some background: this isn’t a post about Genetic Algorithms, but imagine this.
He got to the point where he describes the roulette-style selection process. I’m reading through Classic Computer Science Problems in Python (affiliate link) by David Kopec, and I’m working on his Genetic Algorithm examples.