When I started with Python, I was scared of error messages.
Not because I did not understand the code. Because the red text felt very dramatic.
It took me a while to realise errors are the most useful thing Python does — they tell you precisely where the problem is and why.
Here are the 10 errors every data analyst will see, what they actually mean, and how to fix them:
𝗦𝘆𝗻𝘁𝗮𝘅𝗘𝗿𝗿𝗼𝗿 — Python cannot read what you wrote. Usually a missing bracket, quote, or colon. Read the line above the arrow. That is where the mistake is.
𝗜𝗻𝗱𝗲𝗻𝘁𝗮𝘁𝗶𝗼𝗻𝗘𝗿𝗿𝗼𝗿 — Your spacing is wrong. Use 4 spaces consistently. Never mix tabs and spaces.
𝗡𝗮𝗺𝗲𝗘𝗿𝗿𝗼𝗿 — You used a variable before defining it. Define before you use. Always.
𝗧𝘆𝗽𝗲𝗘𝗿𝗿𝗼𝗿 — You mixed incompatible data types. Convert types before combining them. str(), int(), float() are your first tools.
𝗞𝗲𝘆𝗘𝗿𝗿𝗼𝗿 — You asked for a dictionary key that does not exist. Use .get() instead of square brackets to avoid crashes on missing keys.
𝗜𝗻𝗱𝗲𝘅𝗘𝗿𝗿𝗼𝗿 — You asked for a list position that does not exist. Lists start at 0. The last item is index -1.
𝗔𝘁𝘁𝗿𝗶𝗯𝘂𝘁𝗲𝗘𝗿𝗿𝗼𝗿 — You called a method that does not exist on that object. Check the type first. df.dtypes is your friend.
𝗩𝗮𝗹𝘂𝗲𝗘𝗿𝗿𝗼𝗿 — Right type, wrong value. Use pd.to_numeric(errors='coerce') to handle bad values without crashing.
𝗜𝗺𝗽𝗼𝗿𝘁𝗘𝗿𝗿𝗼𝗿 — The library is not installed or the name is wrong. In Colab use !pip install. Locally use pip install in terminal.
𝗙𝗶𝗹𝗲𝗡𝗼𝘁𝗙𝗼𝘂𝗻𝗱𝗘𝗿𝗿𝗼𝗿 — The file path is wrong. Use os.getcwd() to see where Python is looking, then adjust your path.
Errors are not failures. They are Python telling you exactly what went wrong.