How does Scala's groupBy identity work?

Question

I was browsing around and found a question about grouping a String by it\'s characters, such as this:

The input:

\"aaabbbccccdd\"
         


        

Answer 1

Basically list.groupBy(identity) is just a fancy way of saying list.groupBy(x => x), which in my opinion is clearer. It groups a list containing duplicate items by those items.