How to iterate List in java?

Question

I want to iteate List and If that key is "Happy" then I want to store that in a variable.

Eg:- List<Map> list=service.getValues();

Answer 1

first of all DONT USE RAW Types

after that, do an enhance for loop to iterate the list, every element is a map, then get the entrySet of that

List<Map<String, String>> list = ...;
        for (final Map<String, String> element : list) {
            for (final Entry<String, String> entryElem : element.entrySet()) {
                System.out.println("Key: " + entryElem.getKey());
                System.out.println("Value: " + entryElem.getValue());
            }
        }

---

java8

the nested for loops can be resumed to:

list.forEach(element-> element.entrySet().forEach(System.out::println));

Answer 2

I just traversed the list. Getting the map then travesring the map.

String output="";
            List<Map<String,String>> list=new ArrayList<Map<String,String>>();
            for(int i=0;i<list.size();i++)
            {
                Map<String,String> map=list.get(i);
                Set<String> set=map.keySet();
                Iterator it=set.iterator();
                while(it.hasNext())
                {
                    String key=(String) it.next();
                    if(key.equals("Happy"))
                        output=map.get(key);
                }
            }

Answer 3

    String var=null;
    List<Map> list=new ArrayList<Map>(0);
    for(Map map:list){
    for(Object key:map.keySet()){
    String obj=key.toString(); 
    if(obj.equals("Happy"))
    {
      var=key;
      System.out.println(var);
    }
    }
}

1. Create a List object
2. Iterate through it using enhanced for loop.
3. Store the key one by one in a object(or else you will get Type mismatch error)
4. convert the object into string 5.finally match your string with "Happy"
5. if matches, Stroe it in variable and return successfully.

Answer 4

List<Map> list = service.getValues();    

for(Map map : list) {
    for(String key : map.keySet()) {
        if(key.equals("Happy")) {
           //do something with key
        }
    }
}