its also difficult to understand ternary operators logic at first sight.

I agree with the first comment, that this is no good practice. And I agree that if-else-if-constructs are also no good practice. But as you can see in the frist solution, the else is not even necessary. The result is very easy to read code. You haven't to be a programmer to understand that code. The point is you don't need to get used to it, but to chained ternary operators you have to.

Using chained ternary operators in a uniform way like here isn't bad practice either. It's very easy to grasp that the value literals are increasing upper bounds. Write the same as a chained if-else-if-construct has the advantage to be able to set breakpoints when debugging but also the disadvantage of a worse signal to noise ratio due to many ifs, elses and returns. I think the main reason people still prefer that even in simple cases like this one is that they're used to it. =)

Thanks for sharing this advice. I was thinking this was a clean way of doing it.

Nested ternary operators are a hell to maintain. Not a good practice.

ranks can't be changed

Nesting ternary operators is not a good practice.

I came up with the same solution.

I agree a filter having side effects is a bad practice. But I don't think it is a problem when side effects are limited to a local variable created exclusively for that filter.

This should be 7kyu.

Very clever!

Could be refactored to take advantage of Java 9's map initialization.

Clever, but I don't see how nesting ternary operators is a good practice.

You should always try to find methods, with out withour Google. Is the way to learn!

Love it! Your solution follows my line of thinking but is more streamlined.