HashSet.addAll Arrays.asList split extra space

[Miran Cvenkel]

            //list1 beeing [1,2]
            //HashSet - purpose : prevent duplicates
            HashSet set1 = new HashSet(list1);
            //args[1] beeing "2$3"
            set1.addAll(Arrays.asList(args[1].split("\\$")));
            //looking at (args[27].split("\\$")) in debugger and nicely I see 2 elements, 2 and 3 which is OK
            //what pops out in set1.toString(); is "1,2, 2,3". Note extra space before second 2. 
            // Not what I want obviously.

Looks , to me like a bug ?

[Campbell Ritchie]

What are you splitting on? The $ sign, or line end?

[Miran Cvenkel]

The $ sign.
Point beeing:

System.out.println(args[1]);
System.out.println(set1.toString());

-->
2$3
[1,2, 2, 3]
you see extra spaces before 2 and 3, which appears from nowhere. Hence I get "duplicate" 2

[Winston Gutkowski]

Miran Cvenkel wrote:
[1,2, 2, 3]
you see extra spaces before 2 and 3, which appears from nowhere.

I can guarantee you, it does NOT "appear from nowhere". You also haven't shown us the contents of the original string before the split.

In fact, it might be better to show us a bit more of your code (including the split() call), along with the precise contents of the strings before and after splitting.

Winston

[Miran Cvenkel]

Here you have, test case that proves that something goes wrong in some cases.
Manifestation of that is that some numbers are getting in it with preceding spaces (WRONG), and some are not (OK)

            List list1 = Arrays.asList("13,33");
            list1.removeAll(Arrays.asList("13"));// THIS REMOVES NOTHING ! I suspect coz it thinks that 13 =  " 13"
            
            String arg = "44,55";
            System.out.println(list1);// [13,33]
            HashSet set1 = new HashSet(list1);
            System.out.println(set1);// [13,33]
            System.out.println(arg);//44,55
            if (!arg.equals(""))
            {
              String[] tmpArrStr = arg.split(",");
              //set1.addAll(Arrays.asList(tmpArrStr));
              //attempt zo do somethig about that, but with no effect(-:
              for (int k = 0; k < tmpArrStr.length; k++)
              {
                set1.add(tmpArrStr[k].replaceAll("[^(0-9)]", "").toString());
              }
            }
            System.out.println(set1.toString());//[13,33, 44, 55]

See last out.print, how 13,33 are together and 44,55 pushed to right with space

[Miran Cvenkel]

ahh damn, the secret of this:

[13,33, 44, 55] 

is that 13,33 is all together one element. That is why I was confused.

[Winston Gutkowski]

Miran Cvenkel wrote:is that 13,33 is all together one element. That is why I was confused.

See how good it is when you have to explain a problem in full to someone else?

FYI, To ensure that your elements don't have any extra whitespace in them, you need to trim your input string first and then use something like
split("\\s*,\\s*")
('split on a comma surrounded by any amount of whitespace'). Viz:

String input = "   13,33, 45 , 78 ";
input = input.trim(); // removes leading and trailing whitespace
String[] args = input.split("\\s*,\\s*");
List<String> list1 = Arrays.asList(args); // ALWAYS qualify lists with their element type.
...

HIH

Winston