len() should always return something

Rhodri James rhodri at wildebst.demon.co.uk
Fri Jul 24 16:11:40 CEST 2009


On Fri, 24 Jul 2009 14:57:02 +0100, Grant Edwards <invalid at invalid> wrote:

> On 2009-07-24, Dr. Phillip M. Feldman <pfeldman at verizon.net> wrote:
>>
>> Some aspects of the Python design are remarkably clever, while
>> others leave me perplexed. Here's an example of the latter:
>> Why does len() give an error when applied to an int or float?
>> len() should always return something; in particular, when
>> applied to a scalar, it should return a value of 1.
>
> If len(7) returned a value of 1, then wouldn't one expect 7[0]
> to be valid?  It isn't, so you'd then have to redefine all
> types so that they are sequences that can be indexed.  Sounds
> like a big mess to me...
>
> [Are there types for which len() returns a value that can't be
> indexed?]
>

Dictionaries.

Which doesn't make your point less valid.  In fact I'd go so
far as to argue that what len() gives you is the number of
items in a container, so len(7) should return 0.

-- 
Rhodri James *-* Wildebeest Herder to the Masses



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