How to sort Arraylist of LinkedHashMap Arraylist<LinkedHashMap<String,String>?

Question

How can i sort Arraylist of LinkedHashMap
Ex.

ArrayList<LinkedHashMap<String, String>> list = new ArrayList<LinkedHashMap<String, String>>();
        LinkedHashMap<String, String> linkedHashMap = new LinkedHashMap<String, String>();
        linkedHashMap.put("city", "AB");
        linkedHashMap.put("name", "N");
        linkedHashMap.put("area", "xyz");
        list.add(linkedHashMap);
        linkedHashMap = new LinkedHashMap<String, String>();
        linkedHashMap.put("city", "BA");
        linkedHashMap.put("name", "AB");
        linkedHashMap.put("area", "xyz");
        list.add(linkedHashMap);
        linkedHashMap = new LinkedHashMap<String, String>();
        linkedHashMap.put("city", "CH");
        linkedHashMap.put("name", "AB");
        linkedHashMap.put("area", "PQ");
        list.add(linkedHashMap);

Above is my ArrayList of LinkedHashMap & i want to Sort Value taking Ref as Key (like Sort By City or Sort by name)
I have Done LinkedHashMap(Without Arraylist) Sorting by using Collection.Sort & comparable .
But how can i Sort My Arraylist of LinkedHashMap(Using Loop or Iterator it may possible but is there any other simple way?) Thanks

ArrayList<T> can be sorted only if T implements Comparable interface. So you need to design a custom LinkedHashMap class implementing Comparable and then use Collections.sort() to sort them. — Chandra Sekhar
– Chandra Sekhar, Commented Mar 7, 2012 at 5:35
I would suggest using entities(pojo) instead of linked hash map of storing your object it help you implement comparator. you can find dozen of links by simple google search 'how to sort ArrayList in java'. hope this will help. — Asad Rasheed
– Asad Rasheed, Commented Mar 7, 2012 at 5:44

Rangi Lin · Accepted Answer · 2012-03-07 05:43:21Z

3

You can implement the Comparator<T> and use Collections.sort to sort by the particular value of your LinkedHashMap

However, in you case, you should take advantage of class. Make a class that represent the data inLinkedHashMap

public class MyClass {
    private String city;
    private String name;
    private String area;

    // implement some getters here.
}

Then, again, use Collections.sort, and implement the comparator you want

List<MyClass> myClasses = getMyClasses();
Collections.sort(myClasses, new Comparator<MyClass>(){
    @Override
    public int compare(MyClass o1, MyClass o2) {
        // implement sorting behavior you want.
        return 0;
    }
});

answered Mar 7, 2012 at 5:43

Rangi Lin

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Mahendran · Accepted Answer · 2012-11-22 04:50:34Z

1

Alternatively you can do as follows:

    Collections.sort(list ,
            new Comparator<LinkedHashMap<String, String>>()
            {
                @Override
                public int compare(LinkedHashMap<String, String> obj1,
                        LinkedHashMap<String, String> obj2)
                {
                    return (obj1.get("city").compareTo(obj2.get("city")));
                }
            });

edited Nov 22, 2012 at 4:50

answered Nov 21, 2012 at 12:51

Mahendran

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