Can we modify list while iterating in Java?
The size of the List is not being changed, but the object at the index is changing, so technically the List is being modified. …
How do you modify a list while iterating?
Use a for-loop and list indexing to modify the elements of a list
- a_list = [“a”, “b”, “c”]
- for i in range(len(a_list)): Iterate over numbers `0` up to `2`
- a_list[i] = a_list[i] + a_list[i] Modify value in place.
Can we update list while iterating?
Replace element in arraylist while iterating Do not use iterator if you plan to modify the arraylist during iteration. Use standard for loop, and keep track of index position to check the current element. Then use this index to set the new element.
Can you add to a list while iterating Java?
3 Answers. You can’t modify a Collection while iterating over it using an Iterator , except for Iterator. remove() . This will work except when the list starts iteration empty, in which case there will be no previous element.
Can we modify ArrayList while iterating?
ArrayList provides the remove() methods, like remove (int index) and remove (Object element), you cannot use them to remove items while iterating over ArrayList in Java because they will throw ConcurrentModificationException if called during iteration.
Can we modify ArrayList?
You can modify an ArrayList elementarily (Only one element is added or removed or updated) or in bulk (More than one elements are added or removed or updated).
Can we modify collection while iterating?
In for-each loop, we can’t modify collection, it will throw a ConcurrentModificationException on the other hand with iterator we can modify collection.
Can you add to an ArrayList while iterating?
3. ArrayList listIterator() – Add/Remove. ListIterator supports to add and remove elements in the list while we are iterating over it.
What is the use of list iterator in Java?
ListIterator is one of the four java cursors. It is a java iterator which is used to traverse all types of lists including ArrayList, Vector, LinkedList, Stack etc. It is available since Java 1.2. It extends the iterator interface.
Can we remove elements from ArrayList while iterating?
How can we remove an object from ArrayList?
There are two way to remove an element from ArrayList.
- By using remove() methods : ArrayList provides two overloaded remove() method. a.
- remove(int index) : Accept index of object to be removed. b.
- remove(Object obj) : Accept object to be removed.
Which for loop is faster in Java?
Iterator and for-each loop are faster than simple for loop for collections with no random access, while in collections which allows random access there is no performance change with for-each loop/for loop/iterator.
How to iterate through a list in Java?
An iterator is an object in Java that allows iterating over elements of a collection. Each element in the list can be accessed using iterator with a while loop. ListIterator is an iterator is a java which is available since the 1.2 version. It allows us to iterate elements one-by-one from a List implemented object.
How to remove elements from collection while iterating in Java?
This is supposing that the operation you want to do is “delete”. If you want to “add” this approach would also work, but I would assume you would iterate over a different collection to determine what elements you want to add to a second collection and then issue an addAll method at the end.
Can a stream be modified while iterating in Java?
@Augustas It all depends on how you want to modify this list. But generally you should avoid Iterator which prevents modifying list (removing/adding new elements) while iterating and both streams and for-each loops are using it.
What’s the difference between an iterator and a listiterator?
An iterator is an object in Java that allows iterating over elements of a collection. Each element in the list can be accessed using iterator with a while loop. ListIterator is an iterator is a java which is available since the 1.2 version.