First, the best list on which to discuss this would be Python-Ideas not Python-Dev.
Second, this was brought up there a few months ago, although not much discussion ensued: http://mail.python.org/pipermail/python-ideas/2008-March/001407.html - Eli On Sun, May 18, 2008 at 9:45 PM, Ryan Hitchman <[EMAIL PROTECTED]> wrote: > I'd like to propose an addition to the for statement's syntax: > > for {variable} in {iterable} if {condition}: > {block} > > which is equivalent to > > for {variable} in {iterable}: > if not {condition}: > continue > {block} > > and > > for {variable} in filter(lambda: {condition}, iterable): > {block} > > This would make the syntax closer to that of generators, which have > 'for variable in iterable if condition', and would improve code > clarity by increased brevity and not negating boolean expressions. > > Following are examples of current code with what the new code would > be, taken from the Python 3.0a5 tarball. > > Demo/tkinter/guido/ss1.py:163: > for (x, y), cell in self.cells.items(): > if x <= 0 or y <= 0: > continue > for (x, y), cell in self.cells.items() if x > 0 and y > 0: > > Lib/encodings/__init__.py:91: > for modname in modnames: > if not modname or '.' in modname: > continue > for modname in modnames if modname and '.' not in modname: > > Lib/idlelib/AutoExpand.py:70: > for w in wafter: > if dict.get(w): > continue > for w in wafter if w not in dict: > > Lib/Cookie.py:483: > for K,V in items: > if V == "": continue > if K not in attrs: continue > for K,V in items if V != "" and K not in attrs: > > Lib/hashlib.py:108: > for opensslFuncName in filter(lambda n: n.startswith('openssl_'), > dir(_hashlib)): > for opensslFuncName in dir(_hashlib) if > opensslFuncName.startswith('openssl_'): > > There are many more examples of this in the standard library, and > likely even more in production code. > > I am not familiar with LL(1) parsing, so this may impossible under > that constraint. > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/eli%40courtwright.org >
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