Arrays

Taking an element by its index, changing one, counting, and passing an array to a method.

Section 4.3 laid down the brackets and for … in: several values under one name, taken one at a time. That was all it took to traverse, and no more — the array stayed a queue you follow from start to finish, never able to reach into it.

This section opens it up: reaching an element by its index, changing one, knowing how many there are. And, now that methods return values, passing one as a parameter.

In this section

• 6.1Taking and changing an element

  The index in brackets, .length to count, and the first error of this course that only happens at run time.

• 6.2Traversing by index

  The counted for loop finally earns its keep — and the one-step-too-far shows up at run time.

• 6.3An array parameter

  The array type written out, and the absence of a variadic symbol — a lone value wraps itself.