Welcome to ShenZhenJia Knowledge Sharing Community for programmer and developer-Open, Learning and Share
menu search
person
Welcome To Ask or Share your Answers For Others

Categories

if I use a for-each loop on a linked list in java, is it guaranteed that I will iterate on the elements in the order in which they appear in the list?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
thumb_up_alt 0 like thumb_down_alt 0 dislike
90 views
Welcome To Ask or Share your Answers For Others

1 Answer

I found 5 main ways to iterate over a Linked List in Java (including the Java 8 way):

  1. For Loop
  2. Enhanced For Loop
  3. While Loop
  4. Iterator
  5. Collections’s stream() util (Java8)

For loop

LinkedList<String> linkedList = new LinkedList<>();
System.out.println("==> For Loop Example.");
for (int i = 0; i < linkedList.size(); i++) {
    System.out.println(linkedList.get(i));
}

Enhanced for loop

for (String temp : linkedList) {
    System.out.println(temp);
}

While loop

int i = 0;
while (i < linkedList.size()) {
    System.out.println(linkedList.get(i));
    i++;
}

Iterator

Iterator<String> iterator = linkedList.iterator();
while (iterator.hasNext()) {
    System.out.println(iterator.next()); 
}

collection stream() util (Java 8)

linkedList.forEach((temp) -> {
    System.out.println(temp);
});

One thing should be pointed out is that the running time of For Loop or While Loop is O(n square) because get(i) operation takes O(n) time(see this for details). The other 3 ways take linear time and performs better.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
thumb_up_alt 0 like thumb_down_alt 0 dislike
Welcome to ShenZhenJia Knowledge Sharing Community for programmer and developer-Open, Learning and Share
...