Terry Reedy <tjre...@udel.edu> writes: > J Kenneth King wrote: >> >> Keep in mind that nested comprehensions are still available because >> they do have a use case that justifies their existence. > > Nested comprehensions are available because because the syntax makes > them available by default and making a fiddly exception would be > contrary to Python's style. A list comp creates an iterable. A list > comp requires use of an iterable. Therefore, a list comp may use a > list comp. > >> However, I >> think the Python documentation warns against their use because people >> might rely on them for problems where they aren't necessary and since >> they are difficult to read... it can lead to difficult to read code. > > Whenever the expression that results in the iterable used by a list > comp is sufficiently complex, readability is improved by pulling it > out as a separate statement. Nested list comps are often examplex of > such sufficiently complex expressions, but not the only possible one. > > tjr
Agreed. A very succinct explanation of the point I was trying to make. -- http://mail.python.org/mailman/listinfo/python-list