parse_ranges: first attempt with Bonus1.

parse_ranges/parse_ranges.py

@@ -0,0 +1,19 @@
+def parse_ranges_v1(range_string):
+    """This version causes a memory error for huge ranges..."""
+    ranges = [tuple(map(int, r.split("-"))) for r in range_string.split(",")]
+    result = []
+    for start, stop in ranges:
+        result = [*result, *list(range(start, stop + 1))]
+    for number in result:
+        yield number
+
+
+def parse_ranges_v2(range_string):
+    """This version seems more memory efficient."""
+    ranges = [tuple(map(int, r.split("-"))) for r in range_string.split(",")]
+    for start, stop in ranges:
+        for number in range(start, stop + 1):
+            yield number
+
+
+parse_ranges = parse_ranges_v2

parse_ranges/test_parse_ranges.py

@@ -0,0 +1,42 @@
+import unittest
+
+from parse_ranges import parse_ranges
+
+
+class ParseRangesTests(unittest.TestCase):
+
+    """Tests for parse_ranges."""
+
+    def test_three_ranges(self):
+        self.assertEqual(list(parse_ranges("1-2,4-4,8-10")), [1, 2, 4, 8, 9, 10])
+
+    def test_with_spaces(self):
+        self.assertEqual(
+            list(parse_ranges("0-0, 4-8, 20-21, 43-45")),
+            [0, 4, 5, 6, 7, 8, 20, 21, 43, 44, 45],
+        )
+
+    def test_return_iterator(self):
+        numbers = parse_ranges("0-0, 4-8, 20-21, 43-45")
+        self.assertEqual(next(numbers), 0)
+        self.assertEqual(list(numbers), [4, 5, 6, 7, 8, 20, 21, 43, 44, 45])
+        self.assertEqual(list(numbers), [])
+        numbers = parse_ranges("100-1000000000000")
+        self.assertEqual(next(numbers), 100)
+
+    @unittest.expectedFailure
+    def test_with_individual_numbers(self):
+        self.assertEqual(
+            list(parse_ranges("0,4-8,20,43-45")), [0, 4, 5, 6, 7, 8, 20, 43, 44, 45]
+        )
+
+    @unittest.expectedFailure
+    def test_ignore_arrows(self):
+        self.assertEqual(
+            list(parse_ranges("0, 4-8, 20->exit, 43-45")),
+            [0, 4, 5, 6, 7, 8, 20, 43, 44, 45],
+        )
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)