The following examples show common uses for each tool and demonstrate ways they can be combined.
>>> 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) >>> di = sorted(d.iteritems(), key=itemgetter(1)) >>> for k, g in groupby(di, key=itemgetter(1)): ... print k, map(itemgetter(0), g) ... 1 ['a', 'c', 'e'] 2 ['b', 'd', 'f'] 3 ['g'] # Find runs of consecutive numbers using groupby. The key to the solution # is differencing with a range so that consecutive numbers all appear in # same group. >>> data = [ 1, 4,5,6, 10, 15,16,17,18, 22, 25,26,27,28] >>> for k, g in groupby(enumerate(data), lambda (i,x):i-x): ... print map(operator.itemgetter(1), g) ... [1] [4, 5, 6] [10] [15, 16, 17, 18] [22] [25, 26, 27, 28]
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