Finding length of all values in an ArrayList

Question

For a program I'm attempting to have a nested for loop repeat along the lines of this:

for(int i = 0;i < ArrayList.size();i++){
    for(int x = 0;x <ArrayList.get(i).length();x++){
        //stuff
    }
}

Essentially I want to repeat a for loop for every character in every index of an ArrayList but this solution doesn't seem to work. Any help appreciated!

Edit: the arraylist will only contain strings in my case

Does this ArrayList contains Strings? – Anuradha Oct 24 '18 at 03:19 — Anuradha, Oct 24 '18 at 03:19
@Anuradha the arraylist will only contain strings – Sumtinlazy Oct 24 '18 at 03:21 — Sumtinlazy, Oct 24 '18 at 03:21
What kind of output format do you want? – Andrew Fan Oct 24 '18 at 03:23 — Andrew Fan, Oct 24 '18 at 03:23

score 3 · Accepted Answer · answered Oct 24 '18 at 03:27

3

Try using a For Each Loop such that:

int sumLength = 0;
ArrayList<String> r = new ArrayList<String>();
for(String s : r)
{
 sumLength += s.length();
}
return sumLength;

That will give you the sum of all the lengths in your ArrayList

answered Oct 24 '18 at 03:27

JLiebman

80
7

this did it for me – Sumtinlazy Oct 24 '18 at 07:20

Thina Garan · Answer 2 · 2018-10-24T06:21:18.740

Updated code:

You can use java8 streams to tackle this issue and not to mention is is null-safe. Here is an example.

import java.util.ArrayList;
import java.util.List;

public class NestedList {

    public static void main(String[] args) {

        List<String> list1 = new ArrayList<>();
        list1.add("JOHN");
        list1.add("JACK");
        list1.add("CYTHIA");
        list1.add("DANNY");

        list1.stream().forEach( str -> {
            char x;
            for (int i = 0; i < str.toCharArray().length; i++) {
                x = str.charAt(i);
                //do your struff
                System.out.println(x);
            }
        });

    }
}

The stream method by Java8 will handle the list where as you can use the toCharArray which will convert the string to arrays of character to handle each character.

score 0 · Answer 3 · answered Oct 24 '18 at 03:26

0

You can try this this way,

List<String> arrayList = new ArrayList();

arrayList.add("strings1");
arrayList.add("strings2");

for(int i = 0;i < arrayList.size();i++){
    for(int x = 0;x <arrayList.get(i).length();x++){
          //stuff
    }
}

answered Oct 24 '18 at 03:26

Anuradha

570
6
20

score 0 · Answer 4 · answered Oct 24 '18 at 05:48

all your logic is correct but there is mistake with the syntax, you use Class name instead of object reference, ie, change ArrayList to the ArrayList reference variable in your code.

(ArrayList.size() to list.size())

change

for(int i = 0;i < ArrayList.size();i++){
    for(int x = 0;x <ArrayList.get(i).length();x++){
        //stuff
    }
}

to

ArrayList<String> list = new ArrayList<>();
list.add("apple");
list.add("mango");
list.add("orange");
for(int i = 0;i < list.size();i++){
        for(int x = 0;x <list.get(i).length();x++){
            //stuff
        }
}

Finding length of all values in an ArrayList

4 Answers4