JAVA Linked List How to loop through with a for loop?

Question

Hello I am trying to create a for loop that loops through the linked list. For each piece of data it will list it out individually. I am trying to learn linked list here, so no Array suggestions please. Anyone know how to do this?

Example Output:

Flight 187
Flight 501

CODE I HAVE SO FAR BELOW:

public static LinkedList<String> Flights = new LinkedList<String>();

public flightinfo(){
String[] flightNum = {"187", "501"};
        for (String x : flightNum)
        Flights.add(x);

                for (???)


}

Why are you iterating over the linked list? I'm confused by what you are trying to do. Right now, you have a LinkedList and an array of Strings, and you are iterating over that array of Strings to add them to a LinkedList. I don't understand what your end goal is. — Thomas Owens
– Thomas Owens, Commented Jun 5, 2011 at 20:52

Thomas Jungblut · Accepted Answer · 2014-12-23 19:48:07Z

16

Just use the enhanced for-loop, the same way you'd do it with an array:

for(String flight : flights) {
   // do what you like with it
}

edited Dec 23, 2014 at 19:48

answered Jun 5, 2011 at 20:52

Thomas Jungblut

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Comments

roberttdev · Accepted Answer · 2011-06-05 20:54:51Z

8

If I understand you correctly, you have to get a reference to the List's iterator and use that to cycle through the data:

ListIterator iterator = Flights.iterator(); 
while (iterator.hasNext()){
  System.out.print(iterator.next()+" ");  
}

answered Jun 5, 2011 at 20:54

roberttdev

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Comments

isakkarlsson · Accepted Answer · 2011-06-05 22:12:56Z

2

for(String y : Flights) {
//...
}

The same way as arrays, since it inherits from Iterable<T>

As pointed out by @Cold Hawaiian this only works for Java >= 5.0

If pre 5.0 use:

ListIterator<String> iter = Flights.iterator();
while(iter.hasNext()) {
  String next = iter.next();
  // use next
}

edited Jun 5, 2011 at 22:12

answered Jun 5, 2011 at 20:52

isakkarlsson

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1 Comment

allencoded Over a year ago

This worked I copied the first for loop which was my mistake as it didn't teach me anything. Now I get it though!! Thanks

patapizza · Accepted Answer · 2011-06-05 20:54:14Z

1

You should use a ListIterator (see Java API for more information).

answered Jun 5, 2011 at 20:54

patapizza

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eerpini · Accepted Answer · 2011-06-05 22:30:18Z

0

If you have distinct values in the linked list , this would work :

for(Iterator<String> i = Flights.listIterator(); i.hasNext();){
    String temp = i.next();
    System.out.println(Flights.indexOf(temp)+1+". Flight "+temp );
}

If you do not have distinct values in the linked list, this would work :

int i=0;
for(Iterator<String> iter = Flights.listIterator(); iter.hasNext();i++){
    String temp = iter.next();
    System.out.println(i+1+". Flight "+temp );
}

Hope this helps.

answered Jun 5, 2011 at 22:30

eerpini

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Comments

ozhanli · Accepted Answer · 2017-06-12 09:30:23Z

0

With Java8 Collection classes that implement Iterable have a forEach() method. With forEach() and lambda expressions you can easily iterate over LinkedList

flights.forEach(flight -> System.out.println(flight));

answered Jun 12, 2017 at 9:30

ozhanli

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Comments

Srso · Accepted Answer · 2014-04-30 15:37:35Z

-3

while(!flights.isEmptry) {
  System.out.println(flights.removeFirst());
}

answered Apr 30, 2014 at 15:37

Srso

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