Dealing with `StopIteration` return from a next() call in Python

Question

I'm using the below to skip a group of records when a certain condition is met:

if (condition met):
    ...
    [next(it) for x in range(19)]

Where it is an itertuples object created to speed up looping through a large dataframe (yes, the loop is necessary).

it = df.itertuples()
for row in it:
    ...

What's the idiomatic way of dealing with a StopIteration return from the next call (presumably due to reaching the end of the dataframe)?

Answer 1

So, in general, the solution to a potential exception being raised is to use exception handling. But in the case of next, you can simply use the second argument (which will make it return a default value in case the iterator is exhausted). But you shouldn't use a list comprehension like this anyway, so the most basic solution:

if condition:
    for _ in range(19):
        next(it, None)

But perhaps more elegantly (using the approach from the consume recipe in the itertools docs):

import itertools

def advance(it, n):
    next(itertools.islice(it, n, n), None)

...

if condition:
    advance(it, 19)

But again, a perfectly idiomatic solution would have been:

try:
    [next(it) for x in range(19)]
except StopIteration:
    pass

leaving aside the use of a list comprehension for side-effects