generator&iterator.md

Iterator

Definition

• iterate : 반복하다

iterable Object

• List, Set, Dictionary

How to make a 'Class' to be iterable

• define _iter_ , _next_ (special method, DUNDER method)

For Loop

• Iterable objects can be used at 'for loop' by calling 'next' method.
  • ex) "for a in ["1", "2", "3"]"

Generator

Definition

• Generator is a special form of Iterator
• Every generator should stop at yield, and yield give result partially whenever next method is called.

When to use

• Data is too big to return at once, so need to return partially.

Example

• sample code below

def generator():
   yield 1
   yield 2
   yield 3

g = generator()
print(type(g)) #class generator
n = next(g)
n = next(g)
n = next(g)

for x in generator():
    print(x)

Refer to

• http://pythonstudy.xyz/python/article/23-Iterator%EC%99%80-Generator