The syntax of sort() method is:
list.sort(key=..., reverse=...)

Alternatively, you can also use Python's in-built function sorted() for the same purpose.
sorted(list, key=..., reverse=...)

Note: Simplest difference between sort() and sorted() is: 
sort() doesn't return any value while, sorted() returns an iterable list.

class Person( object ):     
  
        # __init__ is known as the constructor          
        def __init__(self, name, idnumber):    
                self.name = name 
                self.idnumber = idnumber 
        def display(self): 
                print(self.name) 
                print(self.idnumber) 
  
# child class 
class Employee( Person ):            
        def __init__(self, name, idnumber, salary, post): 
                self.salary = salary 
                self.post = post 
  
                # invoking the __init__ of the parent class  
                Person.__init__(self, name, idnumber)  
  
                  
# creation of an object variable or an instance 
a = Person('Rahul', 886012)     
  
# calling a function of the class Person using its instance 
a.display()  

import statistics 
  
# list of positive integer numbers 
data1 = [1, 3, 4, 5, 7, 9, 2] 
  
x = statistics.mean(data1) 
  
# Printing the mean 
print("Mean is :", x)

# None, True, False
# list(), tuple(), dict(), set()

some_list = [-1, 3, 5, -9]
some_dict = dict(x=1,y=3)
print(some_list)

# get only for dict
# print(some_list.get(10, 0)) # list' object has no attribute 'get'
print(some_dict.get("x", 0)) 
# list' object has no attribute 'get', key has to be a string


# enumerate
# for idx, value in enumerate(some_list):
#     print(idx, value)

# reverse()
# This method does not return any value but reverse the given object from the list.
# so print(some_list.reverse()) not working
print(some_list.reverse()) 
# some_list.reverse()
print(some_list)

# min
print(min(some_list))

# string
x = 'bug' * 3
print (x) # prints ‘bugbugbug'

# List
x = [8, 5] * 3
print (x) # prints [8, 5, 8, 5, 8, 5]

# sorting
# – Returns a new list of items in sorted order – Does not change the original list
# String
x = 'bug'
print (sorted(x)) # prints ['b', 'g', 'u']

x = 'bug'
print (x.reverse()) # ERROR 'str' object has no attribute 'reverse'
print (x.sort()) # ERROR 'str' object has no attribute 'sort'
 
#  List
x = ['pig', 'cow', 'horse']
print (sorted(x)) # prints ['cow', 'horse', 'pig']

x = int(1)   # x will be 1
y = int(2.8) # y will be 2
z = int("3") # z will be 3

x = float(1)     # x will be 1.0
y = float(2.8)   # y will be 2.8
z = float("3")   # z will be 3.0
w = float("4.2") # w will be 4.2

x = str("s1") # x will be 's1'
y = str(2)    # y will be '2'
z = str(3.0)  # z will be '3.0'

>>> cubes = [1, 8, 27, 65, 125]  # something's wrong here
>>> 4 ** 3  # the cube of 4 is 64, not 65!
64
>>> cubes[3] = 64  # replace the wrong value
>>> cubes
[1, 8, 27, 64, 125]

word = 'python'
>>> word[:2]   # character from the beginning to position 2 (excluded)
'Py'
>>> word[4:]   # characters from position 4 (included) to the end
'on'
>>> word[-2:]  # characters from the second-last (included) to the end
'on'

All slice operations return a new list containing the requested elements. 
This means that the following slice returns a new (shallow) copy of the list:

>>> squares[:]
[1, 4, 9, 16, 25]

import sys
print(sys.version_info)
print(sys.version)

print("hello world")
print("input your name")
name = input()


def display_name(name):
    if name == "a":
        print(f"name is :{name}")
    elif name == "x":
        print(f"name is : xx {name}")
    else:
        print(f"name is :{name} not a")


display_name(name)

def to_str(bytes_or_str):
    if isinstance(bytes_or_str, bytes):
        value = bytes_or_str.decode(‘utf-8’)
    else:
        value = bytes_or_str
    return value # Instance of str

def to_str(bytes_or_str):
    if isinstance(bytes_or_str, bytes):
        value = bytes_or_str.decode(‘utf-8’)
    else:
        value = bytes_or_str
    return value # Instance of str

a = [‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’, ‘g’, ‘h’]
print(‘First four:’, a[:4])
print(‘Last four: ‘, a[-4:])
print(‘Middle two:’, a[3:-3])
>>>
First four: [‘a’, ‘b’, ‘c’, ‘d’]
Last four: [‘e’, ‘f’, ‘g’, ‘h’]
Middle two: [‘d’, ‘e’]

a[2::2] # [‘c’, ‘e’, ‘g’]
a[-2::-2] # [‘g’, ‘e’, ‘c’, ‘a’]
a[-2:2:-2] # [‘g’, ‘e’]
a[2:2:-2] # []

x = 1
x is 1  # True
x is 0  # False
print(f"x is 1 : {x is 1}")
print(f"x is 0 : {x is 0}")

a = -1
not a  
# this expression  false Negative numbers are just like regular numbers, 
so not (True) is false

x = 0
y = -1
x or y and x - 1 == y and y + 1 == x

# Here it is broken down: x or y # truthy because y is -1 
which is a nonzero value; 
x - 1 == y # true because x - 1 is -1, 
and -1 == -1; x or y
and x - 1 == y # true because both sides of the AND are truthy; 
y + 1 == x # truthy because -1 + 1 does in fact equal zero; 
x or y and x - 1 == y and y + 1 == x 
# also truthy because both sides of the second AND are truthy

a = 1
b = 1
a == b # True
a is b # True

x = [1, 2, 3]
y = [1, 2, 3]
x == y # True
x is y # False

z = y
z == y # True
z is y # True

a = "Hello, World!"
print(a.split(",")) # returns ['Hello', ' World!']

Operator Name Description
-------------------------------------------------
&  AND Sets each bit to 1 if both bits are 1
| OR Sets each bit to 1 if one of two bits is 1
^ XOR Sets each bit to 1 if only one of two bits is 1
~  NOT Inverts all the bits
<< Zero fill left shift Shift left by pushing zeros in from the right and let the leftmost bits fall off
>> Signed right shift Shift right by pushing copies of the leftmost bit in from the left, and let the rightmost bits fall off

colors = ["red", "green", "blue", "purple"]
i = 0
while i < len(colors):
    print(colors[i])
    i += 1
    

colors = ["red", "green", "blue", "purple"]
for i in range(len(colors)):
    print(colors[i])

Yes, remove removes the first matching value, not a specific index:

>>> a = [0, 2, 3, 2]
>>> a.remove(2)
>>> a
[0, 3, 2]
del removes the item at a specific index:

>>> a = [3, 2, 2, 1]
>>> del a[1]
>>> a
[3, 2, 1]
and pop removes the item at a specific index and returns it.

>>> a = [4, 3, 5]
>>> a.pop(1)
3
>>> a
[4, 5]

while val in nums:
        nums.remove(val)

⌘/ Toggle line comment
⇧⌥A Toggle block comment

squares = [1, 4, 9, 16, 25]
print(f"squares : {squares}")  # [1, 4, 9, 16, 25]
print(f"squares[0] : {squares[0]}")  # 1
print(f"squares[-1] : {squares[-1]}")  # 25
print(f"squares[-3:] : {squares[-3:]}")  # [9, 16,5]
print(f"squares[:] : {squares[:]}")  # [1, 4, 9, 16, 25]
concatenation = squares + [36, 49, 64, 81, 100]
# [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
print(f"squares + [36, 49, 64, 81, 100] : {concatenation}")
# Unlike strings, which are immutable,
# lists are a mutable type, i.e.
# it is possible to change their content:
cubes = [1, 8, 27, 65, 125]
cubes[3] = 64
print(f"cubes : {cubes}")
cubes.append(216)
print(f"cubes.append(216) : {cubes}")
cubes.append(7**3)  # 7**3 = 7^3
print(f"cubes.append(7**3) : {cubes}")
cubes[2:5] = ['C', 'D', 'E']  # replace some values
print(f"cubes[2:5] = ['C', 'D', 'E']: {cubes}")  # list not type
cubes[2:5] = []  # remove
print(f"cubes[2:5] = [] : {cubes}")  # list not type
cubes[:] = []  # remove
print(f"cubes[:] = [] : {cubes}")  # list not type
letters = ['a', 'b', 'c', 'd']
print(f"len(letters) : {len(letters)}")
a = ['a', 'b', 'c']
n = [1, 2, 3]
x = [a, n]
print(f"x : {x}")  # [['a', 'b', 'c'], [1, 2, 3]]
print(f"x[0] : {x[0]}")  # ['a', 'b', 'c']
print(f"x[0][1] : {x[0][1]}")  # b

Unlike strings, which are immutable, lists are a mutable type, i.e. it is possible to change their content

for num in range(1, 6):
    print("\U0001f600" * num)

times = 1
while times < 6:
    print("\U0001f600" * times)
    times += 1 #  without this line, it will print forever, 

for num in range(1, 6):
    count = 1
    smileys = ""
    while count <= num:
        smileys += "\U0001f600"
        count += 1
    print(smileys)

for x in "Python_String":
    print(f"🥳 : { x }")

"python_string"[0] # "p"
"python_string"[-1] # "g"
"python_string"[0:3] # "pyt" index 3 is NOT include
"python_string"[0:]  # whole string
"python_string"[:3]  # "pyt"

- \\
- \n
- \"
- \'

f"{first_name} - {last_name}" 

"python_string".upper()
"python_string".lower()
"python string".title() # "Python String"
" python string ".strip() # remove white space
" python string ".lstrip()
" python string ".rstrip()
"python string ".find("str") # return index
"python string ".replace("str","ttt")
print(g in "python string") # return boolean

test_string = "python string"
print(test_string.find("str")) # return index, no found, return "-1"
print("g" in test_string) # return boolean
print("g" not in test_string) # return boolean

x = input("x: "
print(type(x))
bool(x)
int(x)
str(x)
float(x)

matrix = [
    [1, 2, 3, 4],
    [5, 6, 7, 8],
    [9, 10, 11, 12],
]

>>> list(zip(*matrix))
# [(1, 5, 9), (2, 6, 10), (3, 7, 11), (4, 8, 12)]

print(list(zip("abcd", *matrix)))
# [('a', 1, 5, 9), ('b', 2, 6, 10), ('c', 3, 7, 11), ('d', 4, 8, 12)]

# ""
# 0
# None

for x in range(5):
    for y in range(4):
        print(f"({x},{y})")
 
for x in [1, 2, 3, 4]:
    print(f"🥳 : { x }")
    
    
count = 0
for num in range(1, 10):
    if num % 2 == 0:
        count += 1 # NOT count++ snytax error
        print(f"num {num} is even numbers")
print(f"there are {count} even numbers")


words = ["this", "hello is pyton3", "goooooog 🦊"]
for w in words[:]:  # Loop over a slice copy of the entire list.
    if len(w) > 6:
        words.insert(0, w)
print(words)
        

for n in range(2, 10):
    for x in range(2, n):
        if n % x == 0:
            print(n, 'equals', x, '*', n//x)
            break
    else:
        # loop fell through without finding a factor
        print(n, 'is a prime number')

number = 100
while number > 0:
    print(number)
    number //= 2
    
while True:
    command = input("> ").lower()
    if command == "quit":
        break
    else:
        print(f"{command} is not right")

# Fibonacci series:
# the sum of two elements defines the next
a, b = 0, 1 # multiple assignment
while a < 10:
    print(a)
    # print(b)
    a, b = b, a+b # multiple assignment

a = 0
b = 1
while a < 10:
    sum = a + b
    print(a)
    a = b
    b = sum

def greet(frist_name, last_name) # param

greet("Xing", "Wang") # arguments

def get_numbers(*numbers):
    value = 1
    for num in numbers:
        value *= num
    return value


print(get_numbers(1, 2, 3, 4))

def get_user(**user):
    print(user)


get_user(id=1, first_name="xing", age=30)

map(function, iterables)

def myfunc(a, b):
  return a + b

x = map(myfunc, ('apple', 'banana', 'cherry'), ('orange', 'lemon', 'pineapple'))
# ['appleorange', 'bananalemon', 'cherrypineapple']

import random
import math
number = random.randint(25, 50)
a = 100
print(number + a)
print(math.floor(math.pi))
print(math.pi)
print(math.ceil(math.e))
print(math.e)