copysort patch, was RE: [Python-Dev] inline sort option

Dan Aloni da-x at
Sat Oct 18 16:54:41 EDT 2003

On Sat, Oct 18, 2003 at 10:01:52PM +0200, Alex Martelli wrote:
> > >>> (lambda x:(x, x.sort())[0])(list(a))
> This one can, because the lambda lets you give a temporary name x
> to the otherwise-unnamed list returned by D.keys().  It can be made a
> _little_ better, too, I think:
> >>> D=dict.fromkeys('ciao')
> >>> D.keys()
> ['i', 'a', 'c', 'o']
> >>> (lambda x: x.sort() or x)(D.keys())
> ['a', 'c', 'i', 'o']
> and if you want it reversed after sorting,
> >>> (lambda x: x.sort() or x.reverse() or x)(D.keys())
> ['o', 'i', 'c', 'a']

Good, so this way the difference between copied and not 
copied is minimized:

  >>> (lambda x: x.sort() or x)(a)


  >>> (lambda x: x.sort() or x)(list(a))
Nice, this lambda hack is a cleaner, more specific, and simple 
deviation of the chain() function.
Perhaps it could be made more understandable like:

  >>> sorted = lambda x: x.sort() or x
  >>> sorted(list(a))
  ['a', 'c', 'i', 'o']
  >>> sorted(a)
  ['a', 'c', 'i', 'o']

The only problem is that you assume .sort() always returns a non
True value. If some time in the future .sort() would return self, 
your code would break and then the rightful usage would be:

  >>> a = ['c', 'i', 'a', 'o']
  >>> list(a).sort()
  ['a', 'c', 'i', 'o']
  >>> a
  ['c', 'i', 'a', 'o']
  >>> a.sort()
  ['a', 'c', 'i', 'o']
  >>> a
  ['a', 'c', 'i', 'o']

I didn't see the begining of this discussion, but it looks to me that
sort() returning self is much better than adding a .copysort(). 

> BTW, welcome to python-dev!


Dan Aloni
da-x at

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