strtolist2 = Map[FromDigits, StringSplit[StringData[[All, 2]], ","], {-1}] strtolist3 = IntegerPart @ Map[Internal`StringToDouble, StringSplit[StringData[[All, 2]], ","], {-1}]; strtolist3 == strtolist2 == strtolist True
Both are about twice as fast as the For loop with IntegerPart/@Internal`StringToDouble/@StringSplit[@..].