Help required on Array appender

[Vino.B via Digitalmars-d-learn]

Hi All,

 Can you please guide me how can i use array appender for the 
below piece of code

string[][] cleanFiles (string FFs, string Step) {
auto dFiles = dirEntries(FFs, SpanMode.shallow).filter!(a => 
a.isFile).map!(a => tuple(a.name , a.timeCreated)).array;
        foreach (d; dFiles) {
                     if (Step == "dryrun")
                            { Subdata ~=  [d[0], d[1].toSimpleString[0 .. 20]]; 
}
                                  else if (Step == "run") {
                                        remove(d[0]);
                                        if (!d[0].exists)
                                        Subdata ~=  [d[0], 
d[1].toSimpleString[0 .. 20]];
                                                }
                        }
                        return Subdata;
}

From,
Vino.B