Backport documentation improvements.
diff --git a/Doc/lib/libitertools.tex b/Doc/lib/libitertools.tex
index 964bd50..32c0556 100644
--- a/Doc/lib/libitertools.tex
+++ b/Doc/lib/libitertools.tex
@@ -68,6 +68,7 @@
\begin{verbatim}
def chain(*iterables):
+ # chain('ABC', 'DEF') --> A B C D E F
for it in iterables:
for element in it:
yield element
@@ -83,6 +84,7 @@
\begin{verbatim}
def count(n=0):
+ # count(10) --> 10 11 12 13 14 ...
while True:
yield n
n += 1
@@ -100,6 +102,7 @@
\begin{verbatim}
def cycle(iterable):
+ # cycle('ABCD') --> A B C D A B C D A B C D ...
saved = []
for element in iterable:
yield element
@@ -121,6 +124,7 @@
\begin{verbatim}
def dropwhile(predicate, iterable):
+ # dropwhile(lambda x: x<5, [1,4,6,4,1]) --> 6 4 1
iterable = iter(iterable)
for x in iterable:
if not predicate(x):
@@ -156,6 +160,8 @@
\begin{verbatim}
class groupby(object):
+ # [k for k, g in groupby('AAAABBBCCDAABBB')] --> A B C D A B
+ # [(list(g)) for k, g in groupby('AAAABBBCCD')] --> AAAA BBB CC D
def __init__(self, iterable, key=None):
if key is None:
key = lambda x: x
@@ -187,6 +193,7 @@
\begin{verbatim}
def ifilter(predicate, iterable):
+ # ifilter(lambda x: x%2, range(10)) --> 1 3 5 7 9
if predicate is None:
predicate = bool
for x in iterable:
@@ -203,6 +210,7 @@
\begin{verbatim}
def ifilterfalse(predicate, iterable):
+ # ifilterfalse(lambda x: x%2, range(10)) --> 0 2 4 6 8
if predicate is None:
predicate = bool
for x in iterable:
@@ -225,6 +233,7 @@
\begin{verbatim}
def imap(function, *iterables):
+ # imap(pow, (2,3,10), (5,2,3)) --> 32 9 1000
iterables = map(iter, iterables)
while True:
args = [i.next() for i in iterables]
@@ -251,6 +260,10 @@
\begin{verbatim}
def islice(iterable, *args):
+ # islice('ABCDEFG', 2) --> A B
+ # islice('ABCDEFG', 2, 4) --> C D
+ # islice('ABCDEFG', 2, None) --> C D E F G
+ # islice('ABCDEFG', 0, None, 2) --> A C E G
s = slice(*args)
it = iter(xrange(s.start or 0, s.stop or sys.maxint, s.step or 1))
nexti = it.next()
@@ -274,6 +287,7 @@
\begin{verbatim}
def izip(*iterables):
+ # izip('ABCD', 'xy') --> Ax By
iterables = map(iter, iterables)
while iterables:
result = [it.next() for it in iterables]
@@ -311,6 +325,7 @@
\begin{verbatim}
def repeat(object, times=None):
+ # repeat(10, 3) --> 10 10 10
if times is None:
while True:
yield object
@@ -331,6 +346,7 @@
\begin{verbatim}
def starmap(function, iterable):
+ # starmap(pow, [(2,5), (3,2), (10,3)]) --> 32 9 1000
iterable = iter(iterable)
while True:
yield function(*iterable.next())
@@ -343,6 +359,7 @@
\begin{verbatim}
def takewhile(predicate, iterable):
+ # takewhile(lambda x: x<5, [1,4,6,4,1]) --> 1 4
for x in iterable:
if predicate(x):
yield x
@@ -389,34 +406,6 @@
\begin{verbatim}
->>> amounts = [120.15, 764.05, 823.14]
->>> for checknum, amount in izip(count(1200), amounts):
-... print 'Check %d is for $%.2f' % (checknum, amount)
-...
-Check 1200 is for $120.15
-Check 1201 is for $764.05
-Check 1202 is for $823.14
-
->>> import operator
->>> for cube in imap(operator.pow, xrange(1,5), repeat(3)):
-... print cube
-...
-1
-8
-27
-64
-
->>> reportlines = ['EuroPython', 'Roster', '', 'alex', '', 'laura',
- '', 'martin', '', 'walter', '', 'mark']
->>> for name in islice(reportlines, 3, None, 2):
-... print name.title()
-...
-Alex
-Laura
-Martin
-Walter
-Mark
-
# Show a dictionary sorted and grouped by value
>>> from operator import itemgetter
>>> d = dict(a=1, b=2, c=1, d=2, e=1, f=2, g=3)
@@ -529,10 +518,8 @@
def pairwise(iterable):
"s -> (s0,s1), (s1,s2), (s2, s3), ..."
a, b = tee(iterable)
- try:
- b.next()
- except StopIteration:
- pass
+ for elem in b:
+ break
return izip(a, b)
def grouper(n, iterable, padvalue=None):
@@ -543,4 +530,24 @@
"Return a new dict with swapped keys and values"
return dict(izip(d.itervalues(), d))
+def roundrobin(*iterables):
+ "roundrobin('abc', 'd', 'ef') --> 'a', 'd', 'e', 'b', 'f', 'c'"
+ # Recipe credited to George Sakkis
+ pending = len(iterables)
+ nexts = cycle(iter(it).next for it in iterables)
+ while pending:
+ try:
+ for next in nexts:
+ yield next()
+ except StopIteration:
+ pending -= 1
+ nexts = cycle(islice(nexts, pending))
+
+def powerset(iterable):
+ "powerset('ab') --> set([]), set(['a']), set(['b']), set(['a', 'b'])"
+ # Recipe credited to Eric Raymond
+ pairs = [(2**i, x) for i, x in enumerate(iterable)]
+ for n in xrange(2**len(pairs)):
+ yield set(x for m, x in pairs if m&n)
+
\end{verbatim}