What does the underscore mean in literal numbers?

Question

What does that mean?
0.0..10_000.0

Answer 1

It is a Range object, of the kind a..b

In this case it gives you the numbers from 0 to 10,000 as Floats.

the underscore '_' is ignored, and used for readability, so 10_000 is equivalent 10,000.

Buy adding .0 to each part of the range, the numbers would be considered as floats instead of integers, so you won't be able to iterate over the range (the each method would raise an exception).