get number of items in DList

bearophile via Digitalmars-d-learn digitalmars-d-learn at puremagic.com
Fri Jul 11 06:55:45 PDT 2014


Ary Borenszweig:

> So the doubly linked list doesn't know it's length? That seems 
> a bit inefficient...

Have you tried to compile mydList.length or mydList[].length? If 
both don't compile, then you have to walk the items.

Walking the items is not efficient, but:
- Linked lists are very uncommonly needed. In 98-99% of cases an 
array of items or an array of pointers is better (faster for all 
operations, more efficient for memory used, leading to smaller 
binary, more compatible with other APIs, and so on).
- Most functional algorithms that work on lists do not need to 
know the length of the list.

Bye,
bearophile


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