HOW TO CREATE A YOUTUBE CLONE IN PYTHON AND DJANGO

https://www.education-ecosystem.com/andreybu/RaWGm-how-to-create-a-youtube-clone-in-python-and-django/9b4Kz-youtube_webapp/

[🐍PyTricks]: Python list slice syntax fun

Source :  Dan at Real Python <info@realpython.com> 

# Python's list slice syntax can be used without indices
# for a few fun and useful things:

# You can clear all elements from a list:
>>> lst = [1, 2, 3, 4, 5]
>>> del lst[:]
>>> lst
[]

# You can replace all elements of a list
# without creating a new list object:
>>> a = lst
>>> lst[:] = [7, 8, 9]
>>> lst
[7, 8, 9]
>>> a
[7, 8, 9]
>>> a is lst
True

# You can also create a (shallow) copy of a list:
>>> b = lst[:]
>>> b
[7, 8, 9]
>>> b is lst
False

[🐍PyTricks]: Python 3.5+ type annotations

Source : Dan at Real Python <info@realpython.com>

# Python 3.5+ supports 'type annotations' that can be
# used with tools like Mypy to write statically typed Python:

def my_add(a: int, b: int) -> int:
    return a + b

[🐍PyTricks]: Python's list comprehensions are awesome

Source :  Dan at Real Python <info@realpython.com>

# Python's list comprehensions are awesome.

vals = [expression 
        for value in collection 
        if condition]

# This is equivalent to:

vals = []
for value in collection:
    if condition:
        vals.append(expression)

# Example:

>>> even_squares = [x * x for x in range(10) if not x % 2]
>>> even_squares
[0, 4, 16, 36, 64]

[🐍PyTricks]: Python's built-in HTTP server

Source :  Dan at Real Python <info@realpython.com> 

# Python has a HTTP server built into the
# standard library. This is super handy for
# previewing websites.

# Python 3.x
$ python3 -m http.server

# Python 2.x
$ python -m SimpleHTTPServer 8000

# (This will serve the current directory at
#  http://localhost:8000)

Dicts can be used to emulate switch/case statements

Source :  Dan at Real Python <info@realpython.com> 

# Because Python has first-class functions they can
# be used to emulate switch/case statements

def dispatch_if(operator, x, y):
    if operator == 'add':
        return x + y
    elif operator == 'sub':
        return x - y
    elif operator == 'mul':
        return x * y
    elif operator == 'div':
        return x / y
    else:
        return None

def dispatch_dict(operator, x, y):
    return {
        'add': lambda: x + y,
        'sub': lambda: x - y,
        'mul': lambda: x * y,
        'div': lambda: x / y,
    }.get(operator, lambda: None)()


>>> dispatch_if('mul', 2, 8)
16

>>> dispatch_dict('mul', 2, 8)
16

>>> dispatch_if('unknown', 2, 8)
None

>>> dispatch_dict('unknown', 2, 8)
None

Functions are first-class citizens in Python

Source : Dan at Real Python <info@realpython.com> 

# Functions are first-class citizens in Python:

# They can be passed as arguments to other functions,
# returned as values from other functions, and
# assigned to variables and stored in data structures.

>>> def myfunc(a, b):
...     return a + b
...
>>> funcs = [myfunc]
>>> funcs[0]
<function myfunc at 0x107012230>
>>> funcs[0](2, 3)
5

"is" vs "=="

Source :  Dan at Real Python <info@realpython.com> 

# "is" vs "=="

>>> a = [1, 2, 3]
>>> b = a

>>> a is b
True
>>> a == b
True

>>> c = list(a)

>>> a == c
True
>>> a is c
False

# • "is" expressions evaluate to True if two 
#   variables point to the same object

# • "==" evaluates to True if the objects 
#   referred to by the variables are equal

Python's shorthand for in-place value swapping

Source : Dan at Real Python <info@realpython.com>

# Why Python Is Great:
# In-place value swapping

# Let's say we want to swap
# the values of a and b...
a = 23
b = 42

# The "classic" way to do it
# with a temporary variable:
tmp = a
a = b
b = tmp

# Python also lets us
# use this short-hand:
a, b = b, a

Measure the execution time of small bits of Python code with the "timeit" modul

Source :  Dan at Real Python <info@realpython.com>

# The "timeit" module lets you measure the execution
# time of small bits of Python code

>>> import timeit
>>> timeit.timeit('"-".join(str(n) for n in range(100))',
                  number=10000)

0.3412662749997253

>>> timeit.timeit('"-".join([str(n) for n in range(100)])',
                  number=10000)

0.2996307989997149

>>> timeit.timeit('"-".join(map(str, range(100)))',
                  number=10000)

0.24581470699922647