Modifying local variable from inside lambda

Question

Modifying a local variable in forEach gives a compile error:

Normal

    int ordinal = 0;
    for (Example s : list) {
          


        

Answer 1

Yes, you can modify local variables from inside lambdas (in the way shown by the other answers), but you should not do it. Lambdas have been made for functional style of programming and this means: No side effects. What you want to do is considered bad style. It is also dangerous in case of parallel streams.

You should either find a solution without side effects or use a traditional for loop.