Inconsistent reaction to extend

[Bruno Desthuilliers]

Jerzy Karczmarczuk a écrit :
> Gurus, 

No guru answered, so you'll have to bear with me...

> before I am tempted to signal this as a bug, perhaps
> you might convince me that it should be so. If I type
> 
> l=range(4)
> l.extend([1,2])
> 
> l  gives [0,1,2,3,1,2], what else...
> 
> On the other hand, try
> 
> p=range(4).extend([1,2])

> Then, p HAS NO VALUE (NoneType).

But it does have a value : None. And no need to shout, we here you 
pretty well.

Two questions :
1/ Do you *really* think that, *if* it was a bug, no-one would have 
noticed ? Seriously ?

2/ Did you Read The Fine Manual(tm) ?

> 
> WHY?

BECAUSE!

'destructive' methods like append, extend, sort etc return None, so you 
cannot use'em without knowing they are destructive. Rationale is that it 
helps the non-programmers avoiding shooting themselves in the foot. I 
personnaly find it's a PITA, but what, you'll have to live with it, or 
use another language - I, personnaly, choosed to live with it.

BTW, what's wrong with:
  p = range(4) + [1, 2]