I want to compare two ArrayList of objects and find the unmatching values from the second ArrayList based on the ids in the object.
For Example:
Person.java
private int id;
private String name;
private String place;
MainActivity.java:
ArrayList<Person> arrayList1 = new ArrayList<Person>();
arrayList1.add(new Person(1,"name","place"));
arrayList1.add(new Person(2,"name","place"));
arrayList1.add(new Person(3,"name","place"));
ArrayList<Person> arrayList2 = new ArrayList<Person>();
arrayList2.add(new Person(1,"name","place"));
arrayList2.add(new Person(3,"name","place"));
arrayList2.add(new Person(5,"name","place"));
arrayList2.add(new Person(6,"name","place"));
I want to compare the arrayList1, arrayList2 and need to find the unmatching values from the arrayList2. I need the id values 5,6.
How can I do this?
You can use an inner loop, to check if the Person's id from arrayList2
corresponds to any Person id in the arrayList1
. You'll need a flag to mark if some Person was found.
ArrayList<Integer> results = new ArrayList<>();
// Loop arrayList2 items
for (Person person2 : arrayList2) {
// Loop arrayList1 items
boolean found = false;
for (Person person1 : arrayList1) {
if (person2.id == person1.id) {
found = true;
}
}
if (!found) {
results.add(person2.id);
}
}