Best Practices

This is our definitive list of guidelines, suggestions, recommendations, etc
Numbers 1 - 10 are aimed at Beginner Programmers.

1) Use fstrings for string formatting

2) Start your comments where the code starts. (VBA - 6)
SS
Make the indentation of the comment match the indentation of the code it refers to.
Do not left align all your comments.

3) Use meaningful definition names, variable names, etc. (VBA - 10)
Use "snake_case" for variables and functions
Use a name that describes the task they perform.
use descriptive names for loop variables
You should try and use a consistent naming convention.

user_name 
calculate_total() 
Constants - ALL CAPITALS 

4) import only what you need
This makes the dependencies clearer
Group and order the imports in this order - standard library, third-party, local

from math import sqrt 

5) use join() to concatenate strings not (+)
This is faster

join("one", "two", "three") 

6) use isinstance() for type checking not type()

if isinstance(value, int) 

7) Use get() for dictionary access with defaults

age = person.get("age",0) 

8) do not use "==" to compare with none, use is

if value is None 

9) use "in" to check membership, not loops

if item in my_list 

10) use with statement for file handling

with open("file.txt") as f 
    data = f.read() 

11) do not use mutable defaults in function arguments

def add_item(item, items=None) 
    if items is None 
      items = [] 

12) use sorted() instead of sort() when you want a new list
This does not modify the original, it returns a new list that is sorted

new_list = sorted(my_list) 

13) use any() and all() for checking multiple conditions

if any(x > 100 for x in values) 

14) use zip to iterate over multiple sequences together

for name, age in zip(names, ages) 

15) use len() to check if a sequence is empty, not truthiness

if (len(my_list) > 0) 

16) use startswith() and endswith() for string checks
Avoid using arrsays and index like if filename[-5:] = ".xlsx"

if filename.startswith("ab") 
if filename.endswith(".xlsx") 

17) use enumerate() when you need both index and value

for index, item in enumerate(items) 

18) document your definitions with docstrings

def add(a, b) 
    """adds two numbers""" 
   return a + b 

Coding standards

link - peps.python.org/pep-0008/ 

if a_string != "": 
    ... 
# Simplifies to 
if a_string: 
    ... 

if a_number != 0: 
    ... 
# Simplifies to 
if a_number: 
    ... 

def check_senior(age: int) -> bool: 
    # This `if` statement is unnecessary! 
    if age > 60: 
        return True 
    else: 
        return False 
# Exactly equivalent to 
def check_senior(age: int) -> bool: 
    return age > 60 

def check_toddler(age: int): 
    # The `== True` part is redundant! 
    return (age >= 5) == True 
def check_toddler(age: int): 
    # Much better! 
    return age >= 5 

# Defining a function to reverse a string 
def reverse_a_string(): 
    # Reading input from console 
    a_string = input("Enter a string") 
    new_strings = [] 
    
    # Storing length of input string 
    index = len(a_string)    # Reversing the string using while loop 
    while index: 
         index -= 1 
         new_strings.append(a_string[index]) 
    
    #Printing the reversed string 
    print(''.join(new_strings))  
reverse_a_string()