Compare a string with an ArrayList string element

Question

I need some help to fix my issue as I described below:

I have an array list with name datalist and it has elements like ah3w 38 45 1, zj4e 32 4 45. I want to compare a string like ah3w 38 45 1 for checking is it in arraylist or not. The main problem is whitespaces. I want to ignore them because sometimes I have elements in arraylist which has more than one white space between characters. I had tried something like below with using replaceAll method, but it didnt work. Lastly I tried to remove all white space before I created the arraylist, then I did same thing for my string too, it worked but it is not like I want. I dont want to change anything I just want to compare them without spaces. Here is my code example:

String field = "ah3w 38 45 1"
for(int a=0; a<datalist.size(); a++){
   if(datalist.get(a).replaceAll("\\s+","").contains(field.replaceAll("\\s+",""))){
      datalist.remove(a);
   }
}

Here is another code block that is doing same thing and you can run and see what I am trying to do and what ı am getting:

import java.util.ArrayList;

public class ReplaceAllElementsOfArrayListExample {

  public static void main(String[] args) {

    ArrayList arrayList = new ArrayList();
    String field= "ah3w 38 45 1";

    arrayList.add("zj4e 32   4  45");
    arrayList.add("ah3w       38  45   1");
    arrayList.add("ab2 56 2 45");

    System.out.println("Before replacement, ArrayList contains : " + arrayList);

    if(arrayList.get(1).replaceAll("\\s+","").contains(field.replaceAll("\\s+",""))){

    System.out.println("They are equal : " + arrayList);}
    else{
      System.out.println("They are not equal : " + arrayList);  
    }

  }
}

Answer 1

Try this:

    ArrayList<String> arrayList = new ArrayList<String>();
        String field = "ah3w 38 45 1";

        arrayList.add("zj4e 32   4  45");
        arrayList.add("ah3w       38  45   1");
        arrayList.add("ab2 56 2 45");

        //solution
        String fieldNoWhitespaces = field.replaceAll("\\s", "");

        for (String dataElement : arrayList) {
            String arg = dataElement.replaceAll("\\s", "");
            if (fieldNoWhitespaces.equals(arg)) arrayList.remove(dataElement);      
        }
        
        //just to check for correctness
        for (String dataElement : arrayList) {
            System.out.println(":::" + dataElement);

            int count = 0;
            for (int i = 0; i < dataElement.length(); i++) {
                if (Character.isWhitespace(dataElement.charAt(i))) {
                    count++;
                }
            }

        System.out.println(":::Whitespaces:::" + count);
    }

Output:

:::zj4e 32 4 45

:::Whitespaces:::6

:::ab2 56 2 45

:::Whitespaces:::3