Sort ArrayList in reverse order in Java

Question

I am new to the android studio. I want sort this ordersList in reverse order what should I do?

Collections.sort(ordersLists, new Comparator <OrdersList> () {
    @Override
    public int compare(OrdersList ordersList, OrdersList t1) {
        return ordersList.getOrderID().compareToIgnoreCase(t1.getOrderID());
    }
});

Karol Dowbecki · Answer 1 · 2019-03-12T14:27:22.273

4

Use the comparator chain and reversed():

Collections.sort(
    Comparator.comparing(OrderList::getOrderID, String.CASE_INSENSITIVE_ORDER)
              .reversed());

edited Mar 12 '19 at 14:27

answered Mar 12 '19 at 14:23

Karol Dowbecki

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Minor nit: this doesn't ignore case. – Alexey Romanov Mar 12 '19 at 14:25
@AlexeyRomanov thanks, added `CASE_INSENSITIVE_ORDER` – Karol Dowbecki Mar 12 '19 at 14:27

score 2 · Accepted Answer · answered Mar 12 '19 at 14:21

2

You can do it by multiplying the result with -1 e.g.

Collections.sort(ordersLists, new Comparator <OrdersList> () {
    @Override
    public int compare(OrdersList ordersList, OrdersList t1) {
        return ordersList.getOrderID().compareToIgnoreCase(t1.getOrderID()) * -1;
    }
});

answered Mar 12 '19 at 14:21

Murat Karagöz

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1

Or just putting a `-` sign before the expression. – RealSkeptic Mar 12 '19 at 14:22
1

What about `t1.getOrderID().compareToIgnoreCase(ordersList.getOrderID())` ? – lmarqs Mar 12 '19 at 14:23
2

this code won't put a -0 thou – aran Mar 12 '19 at 14:24
This worked for me thanks. – Sudipta Patra Mar 13 '19 at 06:53

score 0 · Answer 3 · answered Mar 12 '19 at 14:23

0

Just call .reversed() on your Comparator.

answered Mar 12 '19 at 14:23

Alexey Romanov

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Sort ArrayList in reverse order in Java

3 Answers3