On Fri, 29 Aug 2008 12:13:34 -0400, "Michael Ash"
<[EMAIL PROTECTED]> wrote:
On Thu, Aug 28, 2008 at 9:50 PM, Gerriet M. Denkmann
<[EMAIL PROTECTED]> wrote:
While if fully agree with you about valid assumptions and so, I am
still
wondering what is the disadvantage of forgetting about
NSEnumerator, Fast
Enumeration and the like and simply doing:
unsigned count = [ array count ];
if ( count == 0 ) return;
for( unsigned i = count - 1;; i--)
{
id a = [ array objectAtIndex: i ];
if ( a is not nice ) [ array removeObjectAtIndex: i ];
if ( i == 0 ) break;
}
Maybe not "Fast" as in "Fast Enumeration" but maybe simpler and
faster than
copying all the "nice" objects into a secondary array.
The disadvantage is simply that it's more code (and therefore more
potential for bugs) and it may be slower.
If performance were not a concern then I'd much prefer something
like this:
for(id obj in [NSArray arrayWithArray: array])
if( condition(obj) )
[array removeObject:obj];
And if performance is a concern, I'd probably prefer something like
this:
NSMutableIndexSet *indexes = [NSMutableIndexSet indexSet];
unsigned index = 0;
for( id obj in array )
{
if(condition(obj))
[indexes addIndex:index];
index++;
}
[array removeObjectsAtIndexes:indexes];
But this is really getting into the realm of personal preference.
Certainly I can't tell you whether this is faster than yours or not,
and the amount of code is such that I wouldn't say that it's
absolutely obvious that it's prettier.
And lastly I just want to note that if your condition fits easily into
an NSPredicate, you can do this whole business as a simple one-liner.
You are right. removeObjectsAtIndexes: is much better than my
suggestion. I did not know about this method.
Another thing I should check out is NSPredicate.
Thanks for enlightening me!
Kind regards,
Gerriet.
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