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Improve extended slicing support in builtin types and classes. Specifically:

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- Specialcase extended slices that amount to a shallow copy the same way as
   is done for simple slices, in the tuple, string and unicode case.

 - Specialcase step-1 extended slices to optimize the common case for all
   involved types.

 - For lists, allow extended slice assignment of differing lengths as long
   as the step is 1. (Previously, 'l[:2:1] = []' failed even though
   'l[:2] = []' and 'l[:2:None] = []' do not.)

 - Implement extended slicing for buffer, array, structseq, mmap and
   UserString.UserString.

 - Implement slice-object support (but not non-step-1 slice assignment) for
   UserString.MutableString.

 - Add tests for all new functionality.
This commit is contained in:
Thomas Wouters 2007-08-28 15:28:19 +00:00
parent 0f4a14b56f
commit 3ccec68a05
16 changed files with 730 additions and 120 deletions
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34
Lib/test/test_array.py
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@ -474,6 +474,18 @@ def test_getslice(self):
array.array(self.typecode)
)
def test_extended_getslice(self):
# Test extended slicing by comparing with list slicing
# (Assumes list conversion works correctly, too)
a = array.array(self.typecode, self.example)
indices = (0, None, 1, 3, 19, 100, -1, -2, -31, -100)
for start in indices:
for stop in indices:
# Everything except the initial 0 (invalid step)
for step in indices[1:]:
self.assertEqual(list(a[start:stop:step]),
list(a)[start:stop:step])
def test_setslice(self):
a = array.array(self.typecode, self.example)
a[:1] = a
@ -557,12 +569,34 @@ def test_setslice(self):
a = array.array(self.typecode, self.example)
self.assertRaises(TypeError, a.__setslice__, 0, 0, None)
self.assertRaises(TypeError, a.__setitem__, slice(0, 0), None)
self.assertRaises(TypeError, a.__setitem__, slice(0, 1), None)
b = array.array(self.badtypecode())
self.assertRaises(TypeError, a.__setslice__, 0, 0, b)
self.assertRaises(TypeError, a.__setitem__, slice(0, 0), b)
self.assertRaises(TypeError, a.__setitem__, slice(0, 1), b)
def test_extended_set_del_slice(self):
indices = (0, None, 1, 3, 19, 100, -1, -2, -31, -100)
for start in indices:
for stop in indices:
# Everything except the initial 0 (invalid step)
for step in indices[1:]:
a = array.array(self.typecode, self.example)
L = list(a)
# Make sure we have a slice of exactly the right length,
# but with (hopefully) different data.
data = L[start:stop:step]
data.reverse()
L[start:stop:step] = data
a[start:stop:step] = array.array(self.typecode, data)
self.assertEquals(a, array.array(self.typecode, L))
del L[start:stop:step]
del a[start:stop:step]
self.assertEquals(a, array.array(self.typecode, L))
def test_index(self):
example = 2*self.example
a = array.array(self.typecode, example)