List comprehension without [ ] in Python

Question

Joining a list:

>>> \'\'.join([ str(_) for _ in xrange(10) ])
\'0123456789\'

join must take an iterable.

Appa

Answer 1

That's a generator, rather than a list comprehension. Generators are also iterables, but rather than creating the entire list first then passing it to join, it passes each value in the xrange one by one, which can be much more efficient.