[Python-Dev] syntactic support for sets

Raymond Hettinger raymond.hettinger at verizon.net
Wed Feb 1 20:50:28 CET 2006

[Greg Wilson]
> I have a student who may be interested in adding syntactic support for
> sets to Python, so that:
>    x = {1, 2, 3, 4, 5}
> and:
>    y = {z for z in x if (z % 2)}
> would be legal.  There are of course issues (what's the syntax for a
> frozen set? for the empty set?), but before he even starts, I'd like to
> know if this would ever be considered for inclusion into the language.

Generator expressions make syntactic support irrelevant:

  x = set(xrange(1,6))
  y = set(z for z in x if (z % 2))
  y = frozenset(z for z in x if (z % 2))

Accordingly,Guido rejected the braced notation for set comprehensions.  
See:  http://www.python.org/peps/pep-0218.html


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