In Python you can have multiple iterators in a list comprehension, like
[(x,y) for x in a for y in b]
for some suitable sequences a and b. I'm aware of the nested loop semantics of Python's list comprehensions.
My question is: Can one iterator in the comprehension refer to the other? In other words: Could I have something like this:
[x for x in a for a in b]
where the current value of the outer loop is the iterator of the inner?
As an example, if I have a nested list:
a=[[1,2],[3,4]]
what would the list comprehension expression be to achieve this result:
[1,2,3,4]
?? (Please only list comprehension answers, since this is what I want to find out).
Gee, I guess I found the anwser: I was not taking care enough about which loop is inner and which is outer. The list comprehension should be like:
[x for b in a for x in b]
to get the desired result, and yes, one current value can be the iterator for the next loop.