reduce() anomaly?
Martin Chilvers
martin at enthought.com
Wed Nov 5 13:42:09 EST 2003
Untested, but try this:-
reduce(lambda x, y: x.update(y) or x, l, {})
The thing you are missing is that the result of x.update is None...
Martin
> -----Original Message-----
> From: python-list-bounces+martin=enthought.com at python.org
> [mailto:python-list-bounces+martin=enthought.com at python.org]
> On Behalf Of Stephen C. Waterbury
> Sent: Wednesday, November 05, 2003 11:18 AM
> To: python list
> Subject: reduce() anomaly?
>
>
> This seems like it ought to work, according to the
> description of reduce(), but it doesn't. Is this
> a bug, or am I missing something?
>
> Python 2.3.2 (#1, Oct 20 2003, 01:04:35)
> [GCC 3.2.2 20030222 (Red Hat Linux 3.2.2-5)] on linux2
> Type "help", "copyright", "credits" or "license" for more
> information. >>> d1 = {'a':1} >>> d2 = {'b':2} >>> d3 =
> {'c':3} >>> l = [d1, d2, d3] >>> d4 = reduce(lambda x, y:
> x.update(y), l) Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> File "<stdin>", line 1, in <lambda>
> AttributeError: 'NoneType' object has no attribute 'update'
> >>> d4 = reduce(lambda x, y: x.update(y), l, {})
> Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> File "<stdin>", line 1, in <lambda>
> AttributeError: 'NoneType' object has no attribute 'update'
>
> - Steve.
>
>
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