digitalmars.D - Deleting from Associate Array during foreach
- teqDruid (formerly DemmeGod) (28/28) Jul 08 2004 Deleting stuff in an associative array while foreaching through it seems
- Vathix (5/31) Jul 08 2004 You're not allowed to do it. "The aggregate itself must not be resized,
- teqDruid (formerly DemmeGod) (7/45) Jul 09 2004 Missed that. Thanks.
- Russ Lewis (6/17) Jul 09 2004 I don't know. Frankly, if it's not specified in the spec, then you
Deleting stuff in an associative array while foreaching through it seems
to mess with the foreach. Is this a bug, or am I doing something wrong?
John
void main()
{
Object[Object] objects;
for(int i=0; i<100; i++)
objects[new Object()] = new Object();
foreach(Object i, Object o; objects)
{
printf("deleting...\n\0");
delete objects[i];
}
}
Produces this output:
$ dmd dtest.d
gcc dtest.o -o dtest -lphobos -lpthread -lm
$ ./dtest
deleting...
deleting...
deleting...
deleting...
deleting...
If the delete line is commented out, a lot of "deleting..." lines are
produced. I haven't counted, but I'd assume there's 100 of them. Does
the array rehash after every 5, and break the foreach or something?
Jul 08 2004
"teqDruid (formerly DemmeGod)" <me teqdruid.com> wrote in message
news:pan.2004.07.09.01.06.42.822388 teqdruid.com...
Deleting stuff in an associative array while foreaching through it seems
to mess with the foreach. Is this a bug, or am I doing something wrong?
John
void main()
{
Object[Object] objects;
for(int i=0; i<100; i++)
objects[new Object()] = new Object();
foreach(Object i, Object o; objects)
{
printf("deleting...\n\0");
delete objects[i];
}
}
Produces this output:
$ dmd dtest.d
gcc dtest.o -o dtest -lphobos -lpthread -lm
$ ./dtest
deleting...
deleting...
deleting...
deleting...
deleting...
If the delete line is commented out, a lot of "deleting..." lines are
produced. I haven't counted, but I'd assume there's 100 of them. Does
the array rehash after every 5, and break the foreach or something?
You're not allowed to do it. "The aggregate itself must not be resized,
reallocated, free'd, reassigned or destructed while the foreach is iterating
over the elements." Loop the objects.keys instead.
Jul 08 2004
Missed that. Thanks. BTW, does anyone know what the behavior of (associative array).keys is? That is, should one be worried about changes being made the the associative array is the array returned by .keys is changed? TIA John On Thu, 08 Jul 2004 21:51:20 -0400, Vathix wrote:"teqDruid (formerly DemmeGod)" <me teqdruid.com> wrote in message news:pan.2004.07.09.01.06.42.822388 teqdruid.com...Deleting stuff in an associative array while foreaching through it seems to mess with the foreach. Is this a bug, or am I doing something wrong? John void main() { Object[Object] objects; for(int i=0; i<100; i++) objects[new Object()] = new Object(); foreach(Object i, Object o; objects) { printf("deleting...\n\0"); delete objects[i]; } } } Produces this output: $ dmd dtest.d gcc dtest.o -o dtest -lphobos -lpthread -lm $ ./dtest deleting... deleting... deleting... deleting... deleting... If the delete line is commented out, a lot of "deleting..." lines are produced. I haven't counted, but I'd assume there's 100 of them. Does the array rehash after every 5, and break the foreach or something?You're not allowed to do it. "The aggregate itself must not be resized, reallocated, free'd, reassigned or destructed while the foreach is iterating over the elements." Loop the objects.keys instead.
Jul 09 2004
Russ Lewis <spamhole-2001-07-16 deming-os.org>
I don't know. Frankly, if it's not specified in the spec, then you
shouldn't assume anything, either.
Although it will cost some performance, a sure-to-be safe thing to do
would be
foreach(Object; objects.keys.dup) { ... }
teqDruid (formerly DemmeGod) wrote:
Missed that. Thanks.
BTW, does anyone know what the behavior of (associative array).keys is?
That is, should one be worried about changes being made the the
associative array is the array returned by .keys is changed?
foreach(Object i, Object o; objects)
{
printf("deleting...\n\0");
delete objects[i];
}
Jul 09 2004