I cant remove a datetime object from my set?

Question

base = datetime.date.today()
dateset = set([base + datetime.timedelta(days=x) for x in range(20)]

for d in dateset:
 if d.weekday() == 0:
  dateset.discard(d)

So as you can see I want to remove any datetime object that has a weekday() of 0.

However the above code throws the error RuntimeError: Set changed size during iteration

Any help is much appreciated.

Answer 1

Rather than creating the set then removing items, you could just only put items into the set that you want in the first place.

Code:

base = datetime.date.today()
dateset = set([base + datetime.timedelta(days=x) for x in range(20) if (base + datetime.timedelta(days=x)).weekday() != 0])

Output:

>>> dateset
{datetime.date(2019, 12, 4),
 datetime.date(2019, 12, 5),
 datetime.date(2019, 12, 6),
 datetime.date(2019, 12, 7),
 datetime.date(2019, 12, 8),
 datetime.date(2019, 12, 10),
 datetime.date(2019, 12, 11),
 datetime.date(2019, 12, 12),
 datetime.date(2019, 12, 13),
 datetime.date(2019, 12, 14),
 datetime.date(2019, 12, 15),
 datetime.date(2019, 12, 17),
 datetime.date(2019, 12, 18),
 datetime.date(2019, 12, 19),
 datetime.date(2019, 12, 20),
 datetime.date(2019, 12, 21),
 datetime.date(2019, 12, 22)}