So I'm trying to create a 2d ArrayList but I'm having some trouble adding one list to another. I found this question that seemed to answer my question but when I try it out myself I get a red warning squiggle under the last add on coordinates.add()
Here's my code
ArrayList<String> coordinates = new ArrayList<String>();
ArrayList<String> buffer = new ArrayList<String>();
buffer.add("123");
buffer.add("abc");
coordinates.add(buffer);
What am I doing wrong here?
you created two arraylist of string name coordinates and buffer. so you can not add one arraylist into a arraylist of string . if you want to add a array list into another then try following code
ArrayList<ArrayList<String>> coordinates = new ArrayList<ArrayList<String>>();
ArrayList<String> buffer = new ArrayList<String>();
buffer.add("123");
buffer.add("abc");
coordinates.add(buffer);
coordinates should be of type ArrayList<ArrayList<String>>
ArrayList<ArrayList<String>> coordinates = new ArrayList<ArrayList<String>>();
Just use addAll method Instead of using add like below:
ArrayList<String> coordinates = new ArrayList<String>();
ArrayList<String> buffer = new ArrayList<String>();
buffer.add("123");
buffer.add("abc");
coordinates.addAll(buffer);
it will not give any error or warning.. thank you..
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