Actually about PEP 202 (listcomps), not (was RE: [Python-Dev] Lukewarm about range literals) (original) (raw)

Fredrik Lundh fredrik@pythonware.com
Tue, 29 Aug 2000 13:49:17 +0200

thomas wrote:

> Saving two characters (":" vs "for") isn't worth it in Python. The > vertical bar would be "worth it" to me, because that's what's used in > SETL, Haskell and common mathematical practice for "such that". Alas, > as Guido is sure to point out, that's too hard to parse

It's impossible to parse, of course, unless you require the parentheses around the expression preceding it :) [ (n) | n in range(100) if n%2 ]

I'm pretty sure Tim meant "|" instead of "if". the SETL syntax is:

[ n : n in range(100) | n%2 ]

(that is, ":" instead of for, and "|" or "st" instead of "if". and yes, they have nice range literals too, so don't take that "range" too literal ;-)

in SETL, that can also be abbreviated to:

[ n in range(100) | n%2 ]

which, of course, is a perfectly valid (though slightly obscure) python expression...