Python Zero to Heros

Online Absolute Beginner Python Tutorials

Every Sunday 2pm (UK time/ BST)

twitch.tv/cheukting_ho

by Cheuk Ting Ho

@cheukting_ho

https://cheuk.dev

Cheukting

Get this slide deck:

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Recap

Beginner topics:

Python objects - int, float, str, list, dict, bool

Control flows - if-else, for loop, while loop

Functions, modeuls, classes and decorators

strings operations and regex with re

Testing:

pytest with fixtures and mock

property-based testing

python linters & auto-formatters

TDD

Intermedite topics:

Iterators

What is Generator?

Generator functions allow you to declare a function that behaves like an iterator, i.e. it can be used in a for loop.

Python generators are a simple way of creating iterators.

Compare to implement a class with __iter__() and __next__() method.

def firstn(n):
	num = 0
	while num < n:
		yield num
		num += 1

Differences between Generator function and Normal function

https://www.programiz.com/python-programming/generator

Generator function contains one or more yield statements.
When called, it returns an object (iterator) but does not start execution immediately.
Methods like __iter__() and __next__() are implemented automatically. So we can iterate through the items using next().
Once the function yields, the function is paused and the control is transferred to the caller.
Local variables and their states are remembered between successive calls.
Finally, when the function terminates, StopIteration is raised automatically on further calls.

Sending to generator

The send() method resumes the generator and sends a value that will be used to continue with the next yield. The method returns the new value yielded by the generator.

- https://stackabuse.com/python-generators/

def numberGenerator(n):
     number = yield
     while number < n:
         number = yield number 
         number += 1

g = numberGenerator(10)    # Create our generator
next(g)                    # 
print(g.send(5))

Python 3.3+ : yield from

def generator1():
    for item in generator2():
        yield item

def generator1():
    yield from generator2()

http://simeonvisser.com/posts/python-3-using-yield-from-in-generators-part-1.html

Next week:
Async

Sunday 2pm (UK time/ BST)