How to take input in ArrayList in java when number of values is not a constant?

Question

I want to take input For example:

550
234234
874982634
3487239482349

The length of the input is not fixed and i want to take input in the array list of java.

ArrayList<Integer> basicpg = new ArrayList<Integer>();

Good luck, you can do it! Try to read [this](http://stackoverflow.com/help/how-to-ask) when you have some time. — User404, Jun 01 '15 at 06:04
Do you want to store your value as single entry or do you want to save each number separately? — PoisonedYouth, Jun 01 '15 at 06:06
User404 is correct: it sounds like you pretty much understand the problem, and basically have the solution. Since the #/items is variable, you want a "List" (e.g. ArrayList). So I guess your question is "How do I input the items?". A: read from System.in, e.g. `Scanner sc = new Scanner(System.in);`. Here are a couple of approaches: http://stackoverflow.com/questions/5488072/reading-in-from-system-in-java — paulsm4, Jun 01 '15 at 06:09
@ak47_kalani follow [this](http://stackoverflow.com/questions/5857812/long-vs-integer-long-vs-int-what-to-use-and-when) — amila isura, Jun 01 '15 at 06:13
Actually I want to take input from the user for example case1-550 case2-3249 case3-73408 , the length of the input is not fixed , i want to add it to array list but the length is not fixed and in one run only one input is fed — ak47_kalani, Jun 01 '15 at 06:30

Uma Kanth · Accepted Answer · 2015-06-01T06:35:57.730

1

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
ArrayList<Integer> basicpg = new ArrayList<Integer>();
String input;
while((input = br.readLine()) != null && input.length() != 0)
{
    basicpg.add(Integer.parseInt(input));
}

1st case If they are space seperated, use .split()

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String input = br.readLine();
String[] tokens = input.split(" ");
List<String> wordList = Arrays.asList(tokens);

enter image description here

edited Jun 01 '15 at 06:35

answered Jun 01 '15 at 06:06

Uma Kanth

5,659
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Actually I want to take input from the user for example case1-550 case2-3249 case3-73408 , the length of the input is not fixed , i want to add it to array list but the length is not fixed and in one run only one input is fed – ak47_kalani Jun 01 '15 at 06:29

score 1 · Answer 2 · edited May 23 '17 at 12:30

ArrayList<Long> basicpg = new ArrayList<Long>();
basicpg.add(550);
basicpg.add(234234);
basicpg.add(874982634);
basicpg.add(3487239482349);

If the Integer length is too long you might want to change it to Long. Integer has a limit & since you are not sure as to what might be the length of the input integer. Check this, or you can put a condition wherein the input integer should be <=Integer.MAX_VALUE

score 0 · Answer 3 · answered Jun 01 '15 at 06:10

0

You may use the following code snippet -

Scanner s = new Scanner(System.in);
ArrayList<Integer> basicpg = new ArrayList<Integer>();

while(s.hasNexInt()){

 Integer i = s.nextInt();
 basicpg.add(i);

}

answered Jun 01 '15 at 06:10

Razib

10,965
11
53
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score 0 · Answer 4 · answered Jun 01 '15 at 06:12

why not just split the input string with space and add it in a loop?

String s = "550 234234 874982634 3487239482349"
ArrayList<Integer> basicpg = new ArrayList<>();
for(ss: s.split()){
    try{
       Integer i = Integer.parseInt(ss);
       basicpg.add(i);
    }catch(Exception e){
       e.printStackTrace();
       contine;
    }
}

How to take input in ArrayList in java when number of values is not a constant?

4 Answers4