python needs leaning stuff from other language

[Diez B. Roggisch]

Tim Wintle schrieb:
> On Sat, 2009-04-04 at 02:03 -0500, Robert Kern wrote:
>> Let's be clear: python-ideas seems positive on the idea of adding a .clear() 
>> method. *Completely removing* slice assignment has not been broached there.
> 
> Yup, sorry - I did mean to refer to the initial suggestion, rather than
> my comments
> 
>>> (I didn't expect such strong responses btw!)
>> You are proposing the removal of a general, orthogonal feature (and breaking 
>> code in consequence!) just because of a new syntax for a single special case of 
>> that feature. That is quite simply ridiculous.
> 
> Ok, I may have come across a little strongly (was very tired) - I'm not
> _actually_ saying we should remove it, I'm just pointing out why
> adding .clear() to lists seems to be unnecessary and slightly messy. The
> suggested removal of assignments to slices is a theoretical statement.
> 
>> .clear() would be non-orthogonal syntactic sugar. That's okay! Python has 
>> syntactic sugar in a number of other places, too! Appropriate doses of syntactic 
>> sugar and non-orthogonality are precisely what lets you implement "There should 
>> be one-- and preferably only one --obvious way to do it." The really key word in 
>> that sentence is "obvious", not "one".
>>
>> FWIW, removing slice assignment would be a gross form of non-orthogonality, too. 
>> __getitem__, __setitem__ and __delitem__ should all be able to accept the same 
>> indices (or else raise exceptions in the case of immutability).
> 
> hummm - I'm sure it would be confusing behaviour if it was not
> available, but I'm not sure how it would be non-orthogonal

 >>> l = range(10)
 >>> l[3:7] = range(4)
 >>> l
[0, 1, 2, 0, 1, 2, 3, 7, 8, 9]

How do you want to do that with clear?

That l[:] = [] clears a list is more of an "accident" than the intent of 
slice-assignment. Removing it in favor of clear() would remove an 
orthogonal feature of updating parts of a list with another iterable.

Diez