I have a array-list which has data from my table. I want to create another array-list only containing integer from 0 to 23. The data has strings, negative numbers. It would be great if someone could give me example of it.
int col = 2;
List values = new ArrayList(table.getRowCount());
for (int row = 0; row < table.getRowCount(); row++) {
values.add(table.getValueAt(row, col));
}
You could do the following-
1. Check if it is a String. If it is, then try parsing the string and if it is successful and it is between 0 and 23, then add to a new list.
2. Check if it is an Integer. If it is, then check if it is between 0 and 23, then add to a new list.
List<Object> inputList; // List containing all kinds of objects
List<Integer> newList = new ArrayList<>();
for (Object o: inputList) {
if (o instanceof String) {
String s = (String) o;
try {
int n = Integer.parseInt(s)
if (n >= 0 && n <= 23) {
newList.add(n);
}
} catch (NumberFormatException e) {
System.out.println(s + " is not an integer");
}
}
else if (o instanceof Integer) {
int n = (Integer)o;
if (n >= 0 && n <= 23) {
newList.add(n);
}
}
}
int n = Integer.parseInt((String) s) . It's perfect for me guys! thank you so much to both of you!!Given the original list is a list of strings List<String> originalList = new ArrayList<>(); the solution would be:
Java8
List<Integer> filteredList = originalList
.stream()
.filter(s -> s.matches("-?[0-9]+")) // filter only strings which contain numbers
.map(Integer::parseInt) // convert them to integers
.filter(v -> v >= 0 && v <= 23) // check if it fits the range
.collect(Collectors.toList());
Java 7
for (String s: originalList) {
if (s.matches("-?[0-9]+")) {
int n = Integer.parseInt(s);
if (n >= 0 && n <= 23) {
filteredList.add(n);
}
}
}
Sample output:
original list: [-10, -9, str, str, str, -5, -4, str, str, -1, 0, 1, 2, str, str, str, str, 7, str, 9]
filtered list: [0, 1, 2, 7, 9]
So you just to copy few items from one list to another and I am assuming they are in sequence.
//Consider you have this list already
List<Object> list = new ArrayList<>(Arrays.asList(1,2,3,4,5,6,7,8,9,10));
//This is the new list you want to create
List<Object> newList = new ArrayList<>();
int i = 0, count = 5;
for(Object o : list){
if(i++ == count) {
break;
}
newList.add(o);
}
System.out.println(newList);
Output: newList : [1, 2, 3, 4, 5]
List<Object> tableValues = new ArrayList<>(Arrays.asList(
new Long(100), new ArrayList(), 3, -6, 20, new Float(1.232), 4));
List<Integer> newValues = new ArrayList<>();
for (Object o : tableValues) {
if (o instanceof Integer) {
if ((Integer)o >= 0 && (Integer)o <= 23) {
newValues.add((Integer)o);
}
}
}
System.out.println(newValues);
Output is [3, 20, 4]
