61 lines
1.6 KiB
Python
61 lines
1.6 KiB
Python
"""Tests para cramers_v."""
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import os
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import random
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import sys
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sys.path.insert(0, os.path.dirname(__file__))
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from cramers_v import cramers_v
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def test_perfect_association_is_near_one():
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a = ["x", "y", "z", "x", "y", "z", "x", "y", "z", "x", "y", "z"]
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b = list(a) # b == a -> asociacion perfecta
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v = cramers_v(a, b)
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assert v > 0.95
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assert v <= 1.0
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def test_independent_columns_low_value():
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rng = random.Random(42)
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cats = ["a", "b", "c", "d"]
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a = [rng.choice(cats) for _ in range(2000)]
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b = [rng.choice(cats) for _ in range(2000)]
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v = cramers_v(a, b)
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assert 0.0 <= v < 0.5
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def test_single_category_returns_zero():
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a = ["only"] * 10 # <2 categorias en a
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b = ["x", "y", "x", "y", "x", "y", "x", "y", "x", "y"]
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assert cramers_v(a, b) == 0.0
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def test_fewer_than_two_pairs_returns_zero():
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assert cramers_v([], []) == 0.0
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assert cramers_v(["a"], ["b"]) == 0.0
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def test_none_pairs_are_discarded():
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a = ["x", None, "y", "x", None, "y", "x", "y"]
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b = ["x", "z", "y", "x", "z", "y", None, "y"]
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v = cramers_v(a, b)
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assert isinstance(v, float)
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assert 0.0 <= v <= 1.0
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def test_always_returns_float_never_none():
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assert isinstance(cramers_v(["a", "b"], ["a", "b"]), float)
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assert isinstance(cramers_v([None], [None]), float)
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def test_derived_column_high_association():
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rng = random.Random(7)
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a = [rng.choice(["red", "green", "blue"]) for _ in range(600)]
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# b derivada de a (mapeo deterministico) -> alta asociacion.
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mapping = {"red": "hot", "green": "cool", "blue": "cool"}
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b = [mapping[x] for x in a]
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v = cramers_v(a, b)
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assert v > 0.5
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