Iterators

Question 1

Iterator

Answer 1

• keeps track of transversal of a container
• iterable object with return an iterator object when you pass it through iter() e.g.
  iterator = iter([1,2,3,])`
• keeps track of current index in iterable, end of iterable

Question 2

Iterator objects

Answer 2

_ _ next _ _ method, return next thing in the iteraiton and update their state/memory of where they are up to
next()
- iterator raises StopIteration exception when container is empty

Question 3

Why use iterators

Answer 3

• memory efficient
• process one item at a time
• avoid generating/copying whole collection
• access each item in turns

Question 4

Iterable

Answer 4

something that could conceptually be accessed element-by-element

Question 5

Iterator

Answer 5

actual interface allowing element by element access

use iterator to access iterable object

Question 6

Itertools

Answer 6

• implements number of iterator building blocks
• standardises set of fast, memory efficient tools
• each tool can be used alone or in combination
  e. g. product, cycle, groupby, combinations