exhausted iterators - what to do about them?

Question

(In Python 3.1) (Somewhat related to another question I asked, but this question is about iterators being exhausted.)

# trying to see the ratio of the max an         


        

Answer 1

Actually your code raises an exception that would prevent this problem! So I guess the problem was that you masked the exception?

>>> min([])
Traceback (most recent call last):
  File "", line 1, in 
ValueError: min() arg is an empty sequence
>>> min(x for x in ())
Traceback (most recent call last):
  File "", line 1, in 
ValueError: min() arg is an empty sequence

Anyways, you can also write a new function to give you the min and max at the same time:

def minmax( seq ):
    " returns the `(min, max)` of sequence `seq`"
    it = iter(seq)
    try:
        min = max = next(it)
    except StopIteration:
        raise ValueError('arg is an empty sequence')
    for item in it:
        if item < min:
            min = item
        elif item > max:
            max = item
    return min, max