I like to measure things. Like token count, line count, variable count, method parameter count, indentation level and grokking time.

Clean code minimizes these measurements.

To minimize variable count I can use ternary expressions. To minimize indentation level I think carefully about early returns or extracting blocks of code to functions that do nothing if condition is true (early return).

To minimize grokking time, I revisit old code I've written and measure the time it takes me to understand it. It turns out it correlates quite a lot with line, variable, and token count, indentation level :D

Clean code as commonly defined is far away from any measurable metrics. That's why one might say that it does not exist.