CODEWITHSUNDEEP
javaarraylistcollections
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Reputation: 1222

How I change a value of a sepecific attribute in all object of LIST

Can i update one attribute in all object in a LIST with a same value when the LIST is loaded, without a loop?`

List<E>myList= new ArrayList<>();
Map<String,List<E>>map;
myList.add(object);// object{attr1,attr2,attr3}
myList.size();//40
//traitement 
map.put(key,myList);

//444+23=[object[attr1=value1, attr2= null, attr3=value3] , object[attr1=value4, attr2= null, attr3=value5]]

map.get(key).set(myList.attr2,value6);
 //result
 //444+23=[object[attr1=value1, attr2= value6, attr3=value3] , object[attr1=value4, attr2= value6, attr3=value5]]

Upvotes: 0

Views: 37

Answers (2)

Ashwani Kumar
Ashwani Kumar

Reputation: 32

No you cant you have to traverse the entire list to do that

Upvotes: 1

Kevin Herron
Kevin Herron

Reputation: 6985

If you have an ArrayList you can use ArrayList#set: http://docs.oracle.com/javase/8/docs/api/java/util/ArrayList.html#set-int-E-

edit: If you're talking about mutating an attribute on every object in the list, then no, you can't do it without some kind of traversal over the entire list.

Upvotes: 1

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