How can i chang the number of row and cols of a 1D array to make it 2D?

Answer 1

You will need to specify the programming language (please use tags).
It would be useful to see your sample code, what your current "array" looks like.
In Python there is no such thing as arraylist, but other languages do have this data type. Python has list, or numpy array, but they are very different in terms of what you want to do in your question.