In Java, how to traverse two lists at the same time?

Question

E.g.

for(String str : list1) {
...
}

for(String str : list2) {
...
}

suppose we are sure that list1.size() equals list2

Answer 1

Use basic loop

for(int index=0; index < list1.size() ; index++){
  list1.get(index);
  list2.get(index);
}

Answer 2

int index = 0;
for(String str1 : list1) {
    str2 = list2.get(index++);
}

Answer 3

You can use iterators:

Iterator<String> it1 = list1.iterator();
Iterator<String> it2 = list2.iterator();
while(it1.hasNext() && it2.hasNext()) { .. }

Or:

for(Iterator<String> it1 = ... it2..; it1.hasNext() && it2.hasNext();) {...} 

Answer 4

You can't traverse two lists at the same time with the enhanced for loop; you'll have to iterate through it with a traditional for loop:

for (int i = 0; i < list1.size(); i++)
{
    String str1 = list1.get(i);
    String str2 = list2.get(i);
    ...
}

Answer 5

for(int i = 0; i< list1.size(); i++){
  String str1 = list1.get(i);
  String str2 = list2.get(i);
  //do stuff
}

Answer 6

As you say that both the list are of same size, then you can use "for" loop instead of "for-each" loop. You can use get(int index) method of list to get the value during each iteration.