%u: > i have qustion why filter can't return int[]
Because a lazy filter is handy, you often don't need a real array result, a lazy sequence is enough. A lazy sequence avoids the memory allocation of the output array. In D programs often the slowest parts are the memory allocations. On the other hand I have asked to add amap/afilter functions that return arrays. Andrei has not answered about this yet. Bye, bearophile
