Am 24.11.2019 um 10:14 schrieb Michael Van Canneyt:


On Sun, 24 Nov 2019, Sven Barth via fpc-pascal wrote:

Am 23.11.2019 um 23:42 schrieb Ryan Joseph via fpc-pascal:
I need a pre-grown list which I can put (not insert!) items into at indexes
without getting "List index out of bounds" errors. For example I want to start with a list that has 10 empty indexes:

list := TList.Create(10); // 10 empty slots!

list[5] := someItem;

Is this possible using any list type in the RTL? Actually I'd rather just
disable all the out of bounds errors becauseĀ  I need some performant which isn't making more checks than need be. I want to use a heap-based list because the it may need to grow later. What you're looking for is the Count property. Setting it is supported by the untyped lists in Classes, the generic ones in FGL as well as those in Generics.Collections.

Better yet, use Capacity.

Count is meant to set the number of slots actually used.
Capacity is the number of allocated slots.
But the setter for the items checks against Count, not Capacity, so the code I showed will fail if used with Capacity instead of Count. At least both properties should be set to work correctly.

Regards,
Sven
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