76 lines
1.9 KiB
Python
76 lines
1.9 KiB
Python
"""
|
|
Providing iterator functions that are not in all version of Python we support.
|
|
Where possible, we try to use the system-native version and only fall back to
|
|
these implementations if necessary.
|
|
"""
|
|
|
|
import itertools
|
|
|
|
def compat_tee(iterable):
|
|
"""
|
|
Return two independent iterators from a single iterable.
|
|
|
|
Based on http://www.python.org/doc/2.3.5/lib/itertools-example.html
|
|
"""
|
|
# Note: Using a dictionary and a list as the default arguments here is
|
|
# deliberate and safe in this instance.
|
|
def gen(next, data={}, cnt=[0]):
|
|
dpop = data.pop
|
|
for i in itertools.count():
|
|
if i == cnt[0]:
|
|
item = data[i] = next()
|
|
cnt[0] += 1
|
|
else:
|
|
item = dpop(i)
|
|
yield item
|
|
next = iter(iterable).next
|
|
return gen(next), gen(next)
|
|
|
|
def groupby(iterable, keyfunc=None):
|
|
"""
|
|
Taken from http://docs.python.org/lib/itertools-functions.html
|
|
"""
|
|
if keyfunc is None:
|
|
keyfunc = lambda x:x
|
|
iterable = iter(iterable)
|
|
l = [iterable.next()]
|
|
lastkey = keyfunc(l[0])
|
|
for item in iterable:
|
|
key = keyfunc(item)
|
|
if key != lastkey:
|
|
yield lastkey, l
|
|
lastkey = key
|
|
l = [item]
|
|
else:
|
|
l.append(item)
|
|
yield lastkey, l
|
|
|
|
# Not really in itertools, since it's a builtin in Python 2.4 and later, but it
|
|
# does operate as an iterator.
|
|
def reversed(data):
|
|
for index in xrange(len(data)-1, -1, -1):
|
|
yield data[index]
|
|
|
|
if hasattr(itertools, 'tee'):
|
|
tee = itertools.tee
|
|
else:
|
|
tee = compat_tee
|
|
if hasattr(itertools, 'groupby'):
|
|
groupby = itertools.groupby
|
|
|
|
def is_iterable(x):
|
|
"A implementation independent way of checking for iterables"
|
|
try:
|
|
iter(x)
|
|
except TypeError:
|
|
return False
|
|
else:
|
|
return True
|
|
|
|
def sorted(in_value):
|
|
"A naive implementation of sorted"
|
|
out_value = in_value[:]
|
|
out_value.sort()
|
|
return out_value
|
|
|