median_low examples

Author: ramalho

less_than/median_low/my_statistics.py

@@ -0,0 +1,25 @@
+from collections.abc import Iterable
+from typing import Any, TypeVar, Protocol
+
+
+class StatisticsError(ValueError):
+    pass
+
+
+class Sortable(Protocol):
+    def __lt__(self, other: Any) -> bool: ...
+
+
+SortableT = TypeVar('SortableT', bound=Sortable)
+
+
+def median_low(data: Iterable[SortableT]) -> SortableT:
+    """Return the low median value of data."""
+    data = sorted(data)
+    n = len(data)
+    if n == 0:
+        raise StatisticsError('no median for empty data')
+    if n % 2 == 1:
+        return data[n // 2]
+    else:
+        return data[n // 2 - 1]

less_than/median_low/my_statistics_test.py

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+from math import isclose
+
+from new_statistics import median_low
+
+
+class SortableThing:
+    def __init__(self, value):
+        self.value = value
+
+    def __lt__(self, other):
+        return self.value < other.value
+
+    def __repr__(self):
+        return f'SortableThing({self.value})'
+
+
+def test_float() -> None:
+    l = [1 / n for n in range(1, 10)]
+    m = median_low(l)
+    assert isclose(m, 1 / 5)
+
+
+def test_str() -> None:
+    l = list('abcd')
+    m = median_low(l)
+    assert m == 'b'
+
+
+def test_sortable_thing() -> None:
+    l = [SortableThing(n) for n in range(1, 8)]
+    m = median_low(l)
+    print(m)
+    assert m.value == 4

less_than/median_low/new_statistics.py

@@ -0,0 +1,25 @@
+from collections.abc import Iterable
+from typing import Any, TypeVar, Protocol
+
+
+class StatisticsError(ValueError):
+    pass
+
+
+class SupportsLessThan(Protocol):
+    def __lt__(self, __other: Any) -> bool: ...
+
+
+SupportsLessThanT = TypeVar('SupportsLessThanT', bound=SupportsLessThan)
+
+
+def median_low(data: Iterable[SupportsLessThanT]) -> SupportsLessThanT:
+    """Return the low median value of data."""
+    data = sorted(data)
+    n = len(data)
+    if n == 0:
+        raise StatisticsError('no median for empty data')
+    if n % 2 == 1:
+        return data[n // 2]
+    else:
+        return data[n // 2 - 1]

less_than/median_low/new_statistics_demo.py

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+from new_statistics import median_low
+
+
+def test_object() -> None:
+    l = [object() for _ in range(1, 10)]
+    try:
+        median_low(l)
+    except TypeError as exc:
+        print(repr(exc))
+
+
+if __name__ == '__main__':
+    test_object()

less_than/median_low/new_statistics_test.py

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+from math import isclose
+
+from new_statistics import median_low
+
+
+class SortableThing:
+    def __init__(self, value):
+        self.value = value
+
+    def __lt__(self, other):
+        return self.value < other.value
+
+    def __repr__(self):
+        return f'SortableThing({self.value})'
+
+
+def test_float() -> None:
+    l = [1 / n for n in range(1, 10)]
+    m = median_low(l)
+    assert isclose(m, 1 / 5)
+
+
+def test_str() -> None:
+    l = list('abcd')
+    m = median_low(l)
+    assert m == 'b'
+
+
+def test_sortable_thing() -> None:
+    l = [SortableThing(n) for n in range(1, 8)]
+    m = median_low(l)
+    print(m)
+    assert m.value == 4

less_than/median_low/old_statistics.py

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+from collections.abc import Iterable
+from decimal import Decimal
+from fractions import Fraction
+from typing import TypeVar
+
+_Number = TypeVar('_Number', float, Decimal, Fraction)
+
+
+class StatisticsError(ValueError):
+    pass
+
+
+def median_low(data: Iterable[_Number]) -> _Number:
+    """Return the low median value of data."""
+    data = sorted(data)
+    n = len(data)
+    if n == 0:
+        raise StatisticsError('no median for empty data')
+    if n % 2 == 1:
+        return data[n // 2]
+    else:
+        return data[n // 2 - 1]

less_than/median_low/old_statistics_test.py

@@ -0,0 +1,33 @@
+from math import isclose
+
+from old_statistics import median_low
+
+
+class SortableThing:
+    def __init__(self, value):
+        self.value = value
+
+    def __lt__(self, other):
+        return self.value < other.value
+
+    def __repr__(self):
+        return f'SortableThing({self.value})'
+
+
+def test_float() -> None:
+    l = [1 / n for n in range(1, 10)]
+    m = median_low(l)
+    assert isclose(m, 1 / 5)
+
+
+def test_str() -> None:
+    l = list('abcd')
+    m = median_low(l)
+    assert m == 'b'
+
+
+def test_sortable_thing() -> None:
+    l = [SortableThing(n) for n in range(1, 8)]
+    m = median_low(l)
+    print(m)
+    assert m.value == 4