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I come from a C++ background and I want to have a matrix of
ArrayList<arrayList<E>> javamatrix In C++ I would just do
std::vector<std::vector<T> > cppmatrix; std::vector<T>vcol(cols); cppmatrix.resize(rows,vcol); I can't seem to find a built-in resize() function for ArrayLists for this task, so should I use another collection? Is no way to do this except using for loops with javamatrix.add()?
P.S I want it to be initialized in the constructor with its size as that size might be queried before I edit elements or add or remove.
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ArrayList class is a resizable array, present in java. util package. The difference between an array and an ArrayList in Java, is that the size of an array cannot be modified (i.e. if you want to append/add or remove element(s) to/from an array, you have to create a new array.
The load factor is the measure that decides when to increase the capacity of the ArrayList. The default load factor of an ArrayList is 0.75f. For example, current capacity is 10. So, loadfactor = 10*0.75=7 while adding the 7th element array size will increase.
trimToSize() method trims the capacity of this ArrayList instance to be the list's current size. An application can use this operation to minimize the storage of an ArrayList instance.
There is no resize equivalent that automatically constructs and adds elements. You must do this yourself. However, ensureCapacity is equivalent to vector's reserve. It will ensure you have room, but not change the actual size.
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