how to remove the [[ from arraylist

[sahana mithra]

I have a value from array list. [[2, 3, 4]]
I just want to remove [[ and ]]. My output should be 2,3,4

I tried pattern.compile([\\[[]);
But i m not able to do it.
Please help me to do this.

[Campbell Ritchie]

How do you get the square brackets? Is it from the toString() method? Have you read its documentation? Why are you getting [[...]] rather than [...]?

Why don't you override that method to print without square brackets?

[sahana mithra]

Hi,
I found the reason. I am getting values from a method which returns as an arrayList and I am storing that in a list again. Here is my code

List dbid=new ArrayList();
                       dbid.add(ar.getdbID());
                       
                       System.out.println("correct----->"+ar.getdbID());
                       String ids=dbid.toString();
                       
                       System.out.println("array"+ids);

Help me to solve this problem. How to remove that [[]]

[Campbell Ritchie]

Override the toString() method. Remove the first and last characters from each element's printout.

[Henry Wong]

Personally, I would recommend not using the toString() method. Use an iterator, a string builder, and create the string that you want -- in the exact format that you want it.

Henry

[jishnu dasgupta]

You might also modify the regex to make it as....\d(,\d)*.....if the pattern is always in the form (number,number,number)....Keeping it greedy will hopefully extract the entire number set and neglect anything else.

[Campbell Ritchie]

Using a regular expression might not help; the output might not always be numbers.

[Jesper de Jong]

So, you have a List inside a List? Then it's perfectly normal that you get it between [[ and ]].

The first [ ] are for the outer list, that contains one element, which is the inner list. The second [ ] are for the inner list.

Why are you storing a list inside a list?