Realising an Iterator

It is sometimes useful to convert an iterator into a concrete sequence such as a list. This is sometimes called “realizing” the iterator.

Reasons for realizing an iterator

There are several reasons you might want to realize an iterator:

• To find its length
• To access the elements more than once (an iterator can only be read from once, afterwards it is spent)
• To access the elements in a different order
• To print it