diff options
Diffstat (limited to 'Lib')
| -rw-r--r-- | Lib/random.py | 4 | ||||
| -rw-r--r-- | Lib/test/test_random.py | 5 |
2 files changed, 8 insertions, 1 deletions
diff --git a/Lib/random.py b/Lib/random.py index be4401c..e24737d 100644 --- a/Lib/random.py +++ b/Lib/random.py @@ -413,8 +413,10 @@ class Random(_random.Random): raise TypeError('Cannot specify both weights and cumulative weights') if len(cum_weights) != n: raise ValueError('The number of weights does not match the population') - bisect = _bisect total = cum_weights[-1] + 0.0 # convert to float + if total <= 0.0: + raise ValueError('Total of weights must be greater than zero') + bisect = _bisect hi = n - 1 return [population[bisect(cum_weights, random() * total, 0, hi)] for i in _repeat(None, k)] diff --git a/Lib/test/test_random.py b/Lib/test/test_random.py index f59c565..2c8c8e8 100644 --- a/Lib/test/test_random.py +++ b/Lib/test/test_random.py @@ -241,6 +241,11 @@ class TestBasicOps: choices = self.gen.choices choices(population=[1, 2], weights=[1e-323, 1e-323], k=5000) + def test_choices_with_all_zero_weights(self): + # See issue #38881 + with self.assertRaises(ValueError): + self.gen.choices('AB', [0.0, 0.0]) + def test_gauss(self): # Ensure that the seed() method initializes all the hidden state. In # particular, through 2.2.1 it failed to reset a piece of state used |