Improve the fidelity of the product() rough equivalent

python · Sep 9, 2024 · 2ffdaa1 · 2ffdaa1
1 parent 903bbfc
commit 2ffdaa1
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
@@ -605,6 +605,8 @@ loops that truncate the stream.
            # product('ABCD', 'xy') → Ax Ay Bx By Cx Cy Dx Dy
            # product(range(2), repeat=3) → 000 001 010 011 100 101 110 111
 
+           if repeat < 0:
+               raise ValueError('repeat argument cannot be negative')
            pools = [tuple(pool) for pool in iterables] * repeat
 
            result = [[]]

diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
@@ -992,12 +992,16 @@ def product1(*args, **kwds):
                 else:
                     return
 
-        def product2(*args, **kwds):
+        def product2(*iterables, repeat=1):
             'Pure python version used in docs'
-            pools = list(map(tuple, args)) * kwds.get('repeat', 1)
+            if repeat < 0:
+                raise ValueError('repeat argument cannot be negative')
+            pools = [tuple(pool) for pool in iterables] * repeat
+
             result = [[]]
             for pool in pools:
                 result = [x+[y] for x in result for y in pool]
+
             for prod in result:
                 yield tuple(prod)