5.16.2 Examples

##
5.16.2 Examples

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]