Thank you, Luca!

I think you'll need a full fledged orchestrator for that. Docker run always starts one container, bit several volumes could be mounted, some of them RW, some RO. I'm not sure about mounting the same folder into several containers (again, orchestration).

You can also use volumes_from argument to mount directory from one container to another.

Works fast too.

Can you please elaborate?

Speed comparison:

Class POI.Test
{

/// do ##class(POI.Test).main()
ClassMethod main(rounds As %Integer = 1000, size As %Integer = 10, nullPercent As %Integer = 20)
{
    set list = ..getList(size, nullPercent)
    
    write !,"Rounds: ", rounds
    write !,"Size: ", size
    write !,"NullPercent: ", nullPercent
    write !,"List: "
    zwrite list
        
    set ways = $lb("listnext", "listfind", "lfs", "base")
    for i=1:1:$ll(ways) {
        set way = $lg(ways, i)
        set start = $zh
        
        set list2 = $classmethod(,way, rounds, list)
        
        set end = $zh
        
        set time = end - start
        
        write !,"Way: ", way
        write !,"Time: ", time
        write !,"List: "
        zwrite list2
        write !
    }
}

ClassMethod base(rounds As %Integer = 1000, list As %List) As %List
{
    for i=1:1:rounds {
        set origList = list
    }
    quit origList
}

ClassMethod listfind(rounds As %Integer = 1000, list As %List)
{
    for i=1:1:rounds {
        set origList = list
        set ptr=0
        for  set ptr=$LISTFIND(origList, $c(0), ptr) quit:'ptr  set $LIST(origList, ptr, ptr)=$lb()
    }
    quit origList
}

ClassMethod listnext(rounds As %Integer = 1000, list As %List)
{
    for i=1:1:rounds {
        set list2 = ""
        set ptr = 0
        while $listnext(list, ptr, elem) {
            if elem'=$C(0) {
                set list2 = list2 _ $LB(elem)
            } else {
                set list2 = list2 _ $LB()
            }
        }
    }
    quit list2
}

ClassMethod lfs(rounds As %Integer = 1000, list As %List)
{
    for i=1:1:rounds {
        set str = $lts(list)
        set str = $tr(str, $c(0))
        set list2 = $lfs(str)    
    }
    quit list2
}

ClassMethod getList(size As %Integer = 10, nullPercent As %Integer = 20) As %List
{
    set list = ""
    for i=1:1:size {
        set list = list _ $lb($select($random(101)<=nullPercent:$c(0),1:$random(50)))
    }
    quit list
}

Results:

POI>do ##class(POI.Test).main(1000000)
 
Rounds: 1000000
Size: 10
NullPercent: 20
List: list=$lb(25,20,$c(0),$c(0),4,42,$c(0),28,44,3)
 
Way: listnext
Time: .944814
List: list2=$lb(25,20,,,4,42,,28,44,3)
 
 
Way: listfind
Time: .610244
List: list2=$lb(25,20,,,4,42,,28,44,3)
 
 
Way: lfs
Time: .430088
List: list2=$lb("25","20","","","4","42","","28","44","3")
 
 
Way: base
Time: .032151
List: list2=$lb(25,20,$c(0),$c(0),4,42,$c(0),28,44,3)

listfind solution seems optimal.

Thanks, Robert.

It works fast, but replaces $c(0) with empty string instead of empty element.

Can $list replace replace $c(0) with empty element?

I posted it as a related question.