# Numbers
x = 5                    # int
y = 3.14                 # float
z = 1 + 2j               # complex
 
# Strings
s = "Hello"
s = 'World'
s = """Multi
line"""
 
# Boolean
b = True
b = False
 
# None
n = None

x = 10
x, y = 5, 10             # Multiple assignment
x, y = y, x              # Swap

# Arithmetic
+ - * / // % **
 
# Comparison
== != < > <= >=
 
# Logical
and or not
 
# Identity
is is not
 
# Membership
in not in

lst = [1, 2, 3]
lst.append(4)            # Add to end
lst.insert(0, 0)         # Insert at index
lst.remove(2)            # Remove value
lst.pop()                # Remove last
lst.pop(0)               # Remove at index
lst.sort()               # Sort in place
sorted(lst)              # Return sorted
lst.reverse()            # Reverse
len(lst)                 # Length
lst[0]                   # Access
lst[-1]                  # Last element
lst[1:3]                 # Slice
lst[::-1]                # Reverse

t = (1, 2, 3)
t = 1, 2, 3              # Without parentheses
t[0]                     # Access
# Tuples are immutable

d = {'key': 'value'}
d['key']                 # Access
d.get('key', default)    # Safe access
d['new'] = 'value'       # Add/update
del d['key']             # Delete
d.keys()                 # All keys
d.values()               # All values
d.items()                # Key-value pairs
'key' in d               # Check existence

s = {1, 2, 3}
s.add(4)                 # Add element
s.remove(2)              # Remove (error if not exists)
s.discard(2)             # Remove (no error)
s1 | s2                  # Union
s1 & s2                  # Intersection
s1 - s2                  # Difference

if condition:
    pass
elif condition:
    pass
else:
    pass
 
# Ternary
x = a if condition else b

# For loop
for item in iterable:
    print(item)
 
for i in range(10):
    print(i)
 
for i, item in enumerate(lst):
    print(i, item)
 
# While loop
while condition:
    pass
 
# Break and continue
break
continue

[x*2 for x in range(10)]
[x for x in range(10) if x % 2 == 0]
{x: x*2 for x in range(5)}  # Dict comprehension
{x*2 for x in range(10)}    # Set comprehension

def function_name(param1, param2):
    return param1 + param2
 
# Default arguments
def func(a, b=10):
    return a + b
 
# Variable arguments
def func(*args, **kwargs):
    pass
 
# Lambda
lambda x: x * 2

@decorator
def function():
    pass
 
# Common decorators
@staticmethod
@classmethod
@property

class MyClass:
    def __init__(self, value):
        self.value = value
    
    def method(self):
        return self.value
 
obj = MyClass(10)
obj.method()

class Child(Parent):
    def __init__(self):
        super().__init__()

# Read
with open('file.txt', 'r') as f:
    content = f.read()
    lines = f.readlines()
    for line in f:
        print(line)
 
# Write
with open('file.txt', 'w') as f:
    f.write('text')
    f.writelines(['line1\n', 'line2\n'])
 
# Append
with open('file.txt', 'a') as f:
    f.write('more text')

import module
from module import function
from module import *
import module as alias

import os
import sys
import json
import datetime
import re
import random
import math

s.lower()
s.upper()
s.strip()
s.split(',')
s.replace('old', 'new')
s.startswith('prefix')
s.endswith('suffix')
s.find('substring')
s.count('char')
','.join(list)
f"Hello {name}"          # f-string

lst.append(x)
lst.extend([1,2,3])
lst.insert(i, x)
lst.remove(x)
lst.pop(i)
lst.clear()
lst.index(x)
lst.count(x)
lst.sort()
lst.reverse()
lst.copy()

try:
    # code
except Exception as e:
    print(e)
except (TypeError, ValueError):
    pass
else:
    # if no exception
finally:
    # always execute
 
# Raise exception
raise ValueError("message")

python -m venv venv
source venv/bin/activate     # Linux/Mac
venv\Scripts\activate        # Windows
deactivate

pip install package
pip install -r requirements.txt
pip freeze > requirements.txt
pip list
pip uninstall package