Katy Brownfield wrote: > On Fri, 6 Jun 2003 18:16:26 +0100, Rob Dixon <[EMAIL PROTECTED]> > wrote: > > > John W. Krahn wrote: > > > Mark Anderson wrote: > > > > > > > > B) You should NEVER use map in a void context. map works very hard > > > > to build up it's return value, so there should be an assignment > > > > (=) operator to the left of your map call almost always, otherwise > > > > all of that work is wasted. > > > > > > I would never say NEVER as there are some situations where it may be > > > appropriate, just like there are some situations where goto is > > > appropriate. > > > > Sure, but I can't for the moment think of any difference between > > > > foreach (LIST) BLOCK > > or > > EXPRESSION foreach LIST > > > > and > > > > map BLOCK LIST > > or > > map EXPRESSION, LIST > > > > in void context. Any thoughts? > > > > Rob > > Mark explained the difference. map has the overhead of building the list > that it returns. foreach doesn't. In Kevin's example a list containing "01" > .. "12" is created and never used. It's inefficient.
Thanks Katy, but John was saying that there were "some situations where it may be be appropriate [to use map in a void context]". I could think of none, since those constructs that I posted using 'foreach' seemed to do exactly the same thing without the overhead that you describe. I wondered if John (or anybody) knew of a difference that I didn't. Rob -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
