add population.entropy()

src/icepool/population/base.py

@@ -683,6 +683,16 @@ def excess_kurtosis(
             self: 'Population[numbers.Rational] | Population[float]') -> float:
         return self.standardized_moment(4) - 3.0
 
+    def entropy(self, base: float = 2.0) -> float:
+        """The entropy of a random sample from this population.
+        
+        Args:
+            base: The logarithm base to use. Default is 2.0, which gives the 
+                entropy in bits.
+        """
+        return -sum(
+            p * math.log(p, base) for p in self.probabilities() if p > 0.0)
+
     # Joint statistics.
 
     class _Marginals(Sequence):

tests/statistics_test.py

@@ -1,6 +1,7 @@
 import icepool
 import pytest
 
+from icepool import Die
 from fractions import Fraction
 
 
@@ -41,3 +42,7 @@ def test_min_quantile():
 def test_max_quantile():
     assert icepool.d6.quantile_low(100) == 6
     assert icepool.d6.quantile_high(100) == 6
+
+
+def test_entropy_with_zeros():
+    assert Die({1: 1, 2: 0, 3: 1}).entropy() == 1.0