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Kill reduce(). A coproduction of John Reese, Jacques Frechet, and Alex M.

This commit is contained in:
Guido van Rossum 2006-08-22 00:21:25 +00:00
parent 6cefeb0e81
commit 89da5d7c3d
10 changed files with 25 additions and 144 deletions
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12
Lib/csv.py
View File

@ -221,12 +221,10 @@ class Sniffer:
if m[n]:
spaces += 1
quotechar = reduce(lambda a, b, quotes = quotes:
(quotes[a] > quotes[b]) and a or b, quotes.keys())
quotechar = max(quotes, key=quotes.get)
if delims:
delim = reduce(lambda a, b, delims = delims:
(delims[a] > delims[b]) and a or b, delims.keys())
delim = max(delims, key=delims.get)
skipinitialspace = delims[delim] == spaces
if delim == '\n': # most likely a file with a single column
delim = ''
@ -285,14 +283,12 @@ class Sniffer:
continue
# get the mode of the frequencies
if len(items) > 1:
modes[char] = reduce(lambda a, b: a[1] > b[1] and a or b,
items)
modes[char] = max(items, key=lambda x: x[1])
# adjust the mode - subtract the sum of all
# other frequencies
items.remove(modes[char])
modes[char] = (modes[char][0], modes[char][1]
- reduce(lambda a, b: (0, a[1] + b[1]),
items)[1])
- sum(item[1] for item in items))
else:
modes[char] = items[0]

3
Lib/difflib.py
View File

@ -652,8 +652,7 @@ class SequenceMatcher:
1.0
"""
matches = reduce(lambda sum, triple: sum + triple[-1],
self.get_matching_blocks(), 0)
matches = sum(triple[-1] for triple in self.get_matching_blocks())
return _calculate_ratio(matches, len(self.a) + len(self.b))
def quick_ratio(self):

6
Lib/idlelib/AutoCompleteWindow.py
View File

@ -335,10 +335,8 @@ class AutoCompleteWindow:
self.userwantswindow = True
return
elif reduce(lambda x, y: x or y,
[keysym.find(s) != -1 for s in ("Shift", "Control", "Alt",
"Meta", "Command", "Option")
]):
elif any(s in keysym for s in ("Shift", "Control", "Alt",
"Meta", "Command", "Option")):
# A modifier key, so ignore
return

22
Lib/idlelib/MultiCall.py
View File

@ -106,24 +106,26 @@ class _SimpleBinder:
# _state_subsets gives for each combination of modifiers, or *state*,
# a list of the states which are a subset of it. This list is ordered by the
# number of modifiers is the state - the most specific state comes first.
# XXX rewrite without overusing functional primitives :-)
_states = range(1 << len(_modifiers))
_state_names = [reduce(lambda x, y: x + y,
[_modifiers[i][0]+'-' for i in range(len(_modifiers))
if (1 << i) & s],
"")
_state_names = [''.join(m[0]+'-'
for i, m in enumerate(_modifiers)
if (1 << i) & s)
for s in _states]
_state_subsets = map(lambda i: filter(lambda j: not (j & (~i)), _states),
_states)
_states)
for l in _state_subsets:
l.sort(lambda a, b, nummod = lambda x: len(filter(lambda i: (1<<i) & x,
range(len(_modifiers)))):
nummod(b) - nummod(a))
# _state_codes gives for each state, the portable code to be passed as mc_state
_state_codes = [reduce(lambda x, y: x | y,
[_modifier_masks[i] for i in range(len(_modifiers))
if (1 << i) & s],
0)
for s in _states]
_state_codes = []
for s in _states:
r = 0
for i in range(len(_modifiers)):
if (1 << i) & s:
r |= _modifier_masks[i]
_state_codes.append(r)
class _ComplexBinder:
# This class binds many functions, and only unbinds them when it is deleted.

26
Lib/test/test_builtin.py
View File

@ -1393,32 +1393,6 @@ class BuiltinTest(unittest.TestCase):
self.assertRaises(OverflowError, range, -sys.maxint, sys.maxint)
self.assertRaises(OverflowError, range, 0, 2*sys.maxint)
def test_reduce(self):
self.assertEqual(reduce(lambda x, y: x+y, ['a', 'b', 'c'], ''), 'abc')
self.assertEqual(
reduce(lambda x, y: x+y, [['a', 'c'], [], ['d', 'w']], []),
['a','c','d','w']
)
self.assertEqual(reduce(lambda x, y: x*y, range(2,8), 1), 5040)
self.assertEqual(
reduce(lambda x, y: x*y, range(2,21), 1L),
2432902008176640000L
)
self.assertEqual(reduce(lambda x, y: x+y, Squares(10)), 285)
self.assertEqual(reduce(lambda x, y: x+y, Squares(10), 0), 285)
self.assertEqual(reduce(lambda x, y: x+y, Squares(0), 0), 0)
self.assertRaises(TypeError, reduce)
self.assertRaises(TypeError, reduce, 42, 42)
self.assertRaises(TypeError, reduce, 42, 42, 42)
self.assertEqual(reduce(42, "1"), "1") # func is never called with one item
self.assertEqual(reduce(42, "", "1"), "1") # func is never called with one item
self.assertRaises(TypeError, reduce, 42, (42, 42))
class BadSeq:
def __getitem__(self, index):
raise ValueError
self.assertRaises(ValueError, reduce, 42, BadSeq())
def test_reload(self):
import marshal
reload(marshal)

13
Lib/test/test_iter.py
View File

@ -498,19 +498,6 @@ class TestCase(unittest.TestCase):
for y in NoGuessLen5(), Guess3Len5(), Guess30Len5():
self.assertEqual(zip(x, y), expected)
# Test reduces()'s use of iterators.
def test_builtin_reduce(self):
from operator import add
self.assertEqual(reduce(add, SequenceClass(5)), 10)
self.assertEqual(reduce(add, SequenceClass(5), 42), 52)
self.assertRaises(TypeError, reduce, add, SequenceClass(0))
self.assertEqual(reduce(add, SequenceClass(0), 42), 42)
self.assertEqual(reduce(add, SequenceClass(1)), 0)
self.assertEqual(reduce(add, SequenceClass(1), 42), 42)
d = {"one": 1, "two": 2, "three": 3}
self.assertEqual(reduce(add, d), "".join(d.keys()))
# This test case will be removed if we don't have Unicode
def test_unicode_join_endcase(self):

4
Lib/test/test_random.py
View File

@ -77,7 +77,9 @@ class TestBasicOps(unittest.TestCase):
pop = range(n)
trials = 10000 # large num prevents false negatives without slowing normal case
def factorial(n):
return reduce(int.__mul__, xrange(1, n), 1)
if n == 0:
return 1
return n * factorial(n - 1)
for k in xrange(n):
expected = factorial(n) // factorial(n-k)
perms = {}

75
Python/bltinmodule.c
View File

@ -1597,80 +1597,6 @@ For example, range(4) returns [0, 1, 2, 3]. The end point is omitted!\n\
These are exactly the valid indices for a list of 4 elements.");
static PyObject *
builtin_reduce(PyObject *self, PyObject *args)
{
PyObject *seq, *func, *result = NULL, *it;
if (!PyArg_UnpackTuple(args, "reduce", 2, 3, &func, &seq, &result))
return NULL;
if (result != NULL)
Py_INCREF(result);
it = PyObject_GetIter(seq);
if (it == NULL) {
PyErr_SetString(PyExc_TypeError,
"reduce() arg 2 must support iteration");
Py_XDECREF(result);
return NULL;
}
if ((args = PyTuple_New(2)) == NULL)
goto Fail;
for (;;) {
PyObject *op2;
if (args->ob_refcnt > 1) {
Py_DECREF(args);
if ((args = PyTuple_New(2)) == NULL)
goto Fail;
}
op2 = PyIter_Next(it);
if (op2 == NULL) {
if (PyErr_Occurred())
goto Fail;
break;
}
if (result == NULL)
result = op2;
else {
PyTuple_SetItem(args, 0, result);
PyTuple_SetItem(args, 1, op2);
if ((result = PyEval_CallObject(func, args)) == NULL)
goto Fail;
}
}
Py_DECREF(args);
if (result == NULL)
PyErr_SetString(PyExc_TypeError,
"reduce() of empty sequence with no initial value");
Py_DECREF(it);
return result;
Fail:
Py_XDECREF(args);
Py_XDECREF(result);
Py_DECREF(it);
return NULL;
}
PyDoc_STRVAR(reduce_doc,
"reduce(function, sequence[, initial]) -> value\n\
\n\
Apply a function of two arguments cumulatively to the items of a sequence,\n\
from left to right, so as to reduce the sequence to a single value.\n\
For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates\n\
((((1+2)+3)+4)+5). If initial is present, it is placed before the items\n\
of the sequence in the calculation, and serves as a default when the\n\
sequence is empty.");
static PyObject *
builtin_reload(PyObject *self, PyObject *v)
{
@ -2071,7 +1997,6 @@ static PyMethodDef builtin_methods[] = {
{"ord", builtin_ord, METH_O, ord_doc},
{"pow", builtin_pow, METH_VARARGS, pow_doc},
{"range", builtin_range, METH_VARARGS, range_doc},
{"reduce", builtin_reduce, METH_VARARGS, reduce_doc},
{"reload", builtin_reload, METH_O, reload_doc},
{"repr", builtin_repr, METH_O, repr_doc},
{"round", (PyCFunction)builtin_round, METH_VARARGS | METH_KEYWORDS, round_doc},

4
Tools/i18n/pygettext.py
View File

@ -462,12 +462,10 @@ class TokenEater:
rentries = reverse[rkey]
rentries.sort()
for k, v in rentries:
isdocstring = 0
# If the entry was gleaned out of a docstring, then add a
# comment stating so. This is to aid translators who may wish
# to skip translating some unimportant docstrings.
if reduce(operator.__add__, v.values()):
isdocstring = 1
isdocstring = any(v.values())
# k is the message string, v is a dictionary-set of (filename,
# lineno) tuples. We want to sort the entries in v first by
# file name and then by line number.

4
Tools/pybench/pybench.py
View File

@ -370,7 +370,7 @@ class Test:
if runs == 0:
return 0.0, 0.0, 0.0, 0.0
min_time = min(self.times)
total_time = reduce(operator.add, self.times, 0.0)
total_time = sum(self.times)
avg_time = total_time / float(runs)
operation_avg = total_time / float(runs
* self.rounds
@ -570,7 +570,7 @@ class Benchmark:
if runs == 0:
return 0.0, 0.0
min_time = min(self.roundtimes)
total_time = reduce(operator.add, self.roundtimes, 0.0)
total_time = sum(self.roundtimes)
avg_time = total_time / float(runs)
max_time = max(self.roundtimes)
return (min_time, avg_time, max_time)