Introduction

Code review is an integral part of a developer’s day-to-day life. Getting mega pint of code review comments has lots of problems but most importantly it hurts developer-ego! I hope you’ll find this article helpful.

Disclaimer: This blog does not claim to be one-and-only solution for all coding problems. Apart from some adopted community guidelines everything is subjective to the coder or reviewer. This is merely my opinions and compiled list of bad coding practices I’ve found through my experience. All the code examples are made to demonstrate a single problem at a time.

1. Variable Names

Bad

temp = {"banana": "yellow", "apple": "red", "grape": "green"}
list1 = []
list2 = []

for k, v in temp.items():
    list1.append(k)
    list2.append(v)

print(f"fruits: {list1}")
print(f"colors: {list2}")

Good

fruit_colors = {"banana": "yellow", "apple": "red", "grape": "green"}
fruits = []
colors = []

for fruit, color in fruit_colors.items():
    fruits.append(fruit)
    colors.append(color)

print(f"fruits: {fruits}")
print(f"colors: {colors}")

Pros

Code readability
Less-prone to bugs

2. Exeption Handling

Bad

try:
    fruit_colors = {"banana": "yellow", "apple": "red", "grape": "green"}
    color = fruit_colors["watermelon"]
except Exception:
    print("Failed to get color of watermelon :(")

Good

fruit_colors = {"banana": "yellow", "apple": "red", "grape": "green"}
try:
    color = fruit_colors["watermelon"]
except KeyError:
    print("Failed to get color of watermelon :(")

Pros

Code readability
Easy troubleshooting

3. Utilizing Standard Library

Bad

fruits = ["apple", "banana", "grape"]

i = 0
for fruit in fruits:
    print(f"{i}: {fruit}")
    i += 1

Good

fruits = ["apple", "banana", "grape"]

for i, fruit in enumerate(fruits):
    print(f"{i}: {fruit}")

Pros

Compact

4. Error Logging

Bad

try:
    res = requests.get("https://www.google.com")
    res.raise_for_status()
    logging.info("Success!")
except Exception as e:
    logging.error(f"Unexpected error occured: {e}")

Good

try:
    res = requests.get("https://www.google.com")
    res.raise_for_status()
    logging.info("Success!")
except HTTPError as err:
    logging.error(
        f"Request failed with status code: {err.response.status_code}"
    )
except Exception:
    # logging.exception logs traceback information
    logging.exception("Unexpected error occured:")

Pros

Code readability
Easy troubleshooting

5. Block Comments

Bad

username = username.lower()
username = username.strip()
username = re.sub(r"\s+", "", username)
if not re.match(r"^[a-zA-Z0-9_]{5,20}$", username):
    print("Invalid username")
    exit(1)

Good

# Perform string transforms on the username
username = username.lower()
username = username.strip()
username = re.sub(r"\s+", "", username)

# Check if username is valid
if not re.match(r"^[a-zA-Z0-9_]{5,20}$", username):
    print("Invalid username")
    exit(1)

Pros

Code readability

Conclusion

This blog is a part of a series and each of these points can be extended with some advanced scenarios. Unfortunately, I can’t mention all the scenarios in a single blog so I will try to cover other cases in future parts. Feel free to reach out if you have any questions, suggestions for improvments or any good coding practice you’ve found.