Can we modify Collection while iterating?

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.

How do you modify a list while iterating?

Use a for-loop and list indexing to modify the elements of a list

1. a_list = [“a”, “b”, “c”]
2. for i in range(len(a_list)): Iterate over numbers `0` up to `2`
3. a_list[i] = a_list[i] + a_list[i] Modify value in place.

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. …

Is Iterator faster than for loop C++?

Iterating over a vector using iterators is not faster and is not safer (actually if the vector is possibly resized during the iteration using iterators will put you in big troubles). The idea of having a generic loop that works when you will change later the container type is also mostly nonsense in real cases.

Can you change I in for loop?

For this reason, for loops in Python are not suited for permanent changes to the loop variable and you should resort to a while loop instead, as has already been demonstrated in Volatility’s answer.

How do you modify a list in Java?

To replace an existing element, we must find the exact position (index) of the element in arraylist. Once we have the index, we can use set() method to update the replace the old element with new element. Find index of existing element using indexOf() method. Use set(index, object) to update new element.

Can we remove any element by using it for each loop?

Unfortunately, you cannot use it everywhere. Consider, for example, the expurgate method. The program needs access to the iterator in order to remove the current element. The for-each loop hides the iterator, so you cannot call remove .

How can we remove an Object from ArrayList?

There are two way to remove an element from ArrayList.

1. By using remove() methods : ArrayList provides two overloaded remove() method. a.
2. remove(int index) : Accept index of object to be removed. b.
3. remove(Object obj) : Accept object to be removed.