13)Java Misc.:

Java Misc.:

• Length: array.length; ArrayList.size(); string.length();
• HashMap<T>.put(key, value); map.get(key);
• ArrayList:
  • add(element)
  • contains(element)
  • get(index)
• LinkedList:
  • add(element)
    With or without an additional index argument. Without, adds to tail.
  • remove(element/index)
  • get(index)
  • getFirst()
    Dequeue if implementing queue.
  • list.size()
• Stack:
  • empty()
  • peek()
  • pop()
  • push(element)
  • search(element)
    Returns offset from top of stack.
• Arrays.sort(primitiveArray);
• Collections.sort(arrayList);
• Primitive arrays have to be initialized with a capacity, ArrayLists don't -- they dynamically grow.
• currChar = theStr.charAt(i);
• From char to String and back:
  • String s = String.valueOf(c);
  • char c = s.charAt(0);
  • char[] chars = s.toCharArray();
• From int to String and back:
  • String str = String.valueOf(foo);
    Note that this is the same as above!
  • int foo = Integer.parseInt(str)
• The conditional operator can seem weird:
  • int x = booleanExpr ? thisNum : thatNum;
    Note that it has to return a value.
  • But it's just equivalent to this:
    • if (booleanExpr) x = thisNum;
    • else { x = thatNum; }