Lesson 3 Notes

Lesson 3 Notes

Array = a list with a fixed size

[[1],[2],[3],[4],[5]]
In Python this is a list of lists
not an array in python

in scala we need to say what type of array it is
[45,60,27,3,41] indices 0-4

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val numbers: Array[Int] = Array(45,60,27,3,41)
it is a fixed size
has to hold the same type

if we know the index it takes CONSTANT TIME to find elements in arrays

if I don't know the index then I'll start at the beginning and look for the given value-- LINEAR TIME

Arrays are mutable-- n(2) = 74
updating an array

val two = n(2) // ezpz

If i want to add to an array that's already full I need to make a new one, that would be really warm and bad
so we will use a list instead!

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Lists are made up of nodes that are made up of values and stuff-- each is a value and a pointer that points to the next node (as opposed to arrays that are just a pointer to a fixed set of values)
the last one points to nothing / null

doesn't take constant time to find stuff in arrays by index-- LINEAR TIME instead