Call to
next() should be wrapped in try-except 90 return [i for (i, isprime) in enumerate(listPrimality(n)) if isprime]
91
92def nthPrime(n):
93 return next(itertools.islice(filter(isPrime, itertools.count(2)), n-1, None)) 94
95
96def nthRoot(num, root) -> float:
Description
Calls to next() should be inside try-except block.
When the iterator is exhausted, StopIteration exception is raised. When used inside a generator, this can cause unexpected behavior. If not handled, it will propagate out of the generator causing termination. PEP-479 has been accepted to fix this problem. It will modify the behavior of StopIteration in generators.
Each call to next() should be wrapped in a try-except block to explicitly handle StopIteration exceptions.
Bad practice
def get_team_structure(team):
for team in class:
students = iter(team)
# StopIteration exception will be raised if team doesn't have members.
leader = next(students)
members = [m for m in students]
yield leader, members
def print_teams(teams):
for leader, members in get_team_structure(teams):
print("Leader: "leader)
for member in members:
print(member)
Recommended:
def get_team_structure(team):
for team in class:
# StopIteration exception will be raised if team has no members.
students = iter(team)
# Added `try` block, to guard against the exception
try:
leader = next(students)
except StopIteration:
# team has no members, skip it
continue
members = [m for m in students]
yield leader, members
def print_teams(teams):
for leader, members in get_team_structure(teams):
print("Leader: "leader)
for member in members:
print(member)
...