# Error with first assignment **URL:** \ **Category:** Supervised ML: Regression and Classification\ **Tags:** week-module-2\ **Created:** [October 27, 2022, 1:38pm UTC](https://community.deeplearning.ai/t/error-with-first-assignment/223128 "2022-10-27T13:38:46Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Fatma\_Yehia](https://avatars.discourse-cdn.com/v4/letter/f/ecae2f/32.png) [@Fatma\_Yehia](https://community.deeplearning.ai/u/Fatma_Yehia)\ **Post date:** [October 27, 2022, 1:38pm UTC](https://community.deeplearning.ai/t/error-with-first-assignment/223128/1 "2022-10-27T13:38:46Z")
![16668780190123383337908619286124](https://global.discourse-cdn.com/dlai/original/3X/9/1/91e42be1cd134dae3cc40d4d741553c05490e43d.jpeg) I can’t know how to solve this error. ---
**Author:** ![Enzo\_Faliveni\_Alzuet](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/enzo_faliveni_alzuet/32/30842_2.png) [@Enzo\_Faliveni\_Alzuet](https://community.deeplearning.ai/u/Enzo_Faliveni_Alzuet)\ **Post date:** [October 27, 2022, 2:51pm UTC](https://community.deeplearning.ai/t/error-with-first-assignment/223128/2 "2022-10-27T14:51:54Z")
Hi Fatma! In the first place, remember that you are only supposed to edit the code between `### START CODE HERE ###` and `### END CODE HERE ###`. Second, the function `compute_cost` returns a **float** : `total_cost`, which is the cost of using w, and b as the parameters for linear regression to fit the data points in x and y. According to the TypeError: unsupported format string passed to numpy.ndarray I believe your output is a NumPy ndarray. Cheers, ---
**Author:** ![Fatma\_Yehia](https://avatars.discourse-cdn.com/v4/letter/f/ecae2f/32.png) [@Fatma\_Yehia](https://community.deeplearning.ai/u/Fatma_Yehia)\ **Post date:** [October 27, 2022, 3:34pm UTC](https://community.deeplearning.ai/t/error-with-first-assignment/223128/3 "2022-10-27T15:34:22Z")
Yes, it is. I just search for how can I solve it since I don’t know any experience with python before ---
**Author:** ![ritik5](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@ritik5](https://community.deeplearning.ai/u/ritik5)\ **Post date:** [October 27, 2022, 4:08pm UTC](https://community.deeplearning.ai/t/error-with-first-assignment/223128/4 "2022-10-27T16:08:05Z")
Did you get your answer right? If not then use print(f’Cost at initial w: {cost:.3f}‘) instead of: print(f’(Cost at initial w: {cost:.3f})') . Getting familiar with Python is helpful for this course, Checkout this [Programming for Everybody (Getting Started with Python)](https://www.coursera.org/learn/python?specialization=python) course. ---
**Author:** ![Fatma\_Yehia](https://avatars.discourse-cdn.com/v4/letter/f/ecae2f/32.png) [@Fatma\_Yehia](https://community.deeplearning.ai/u/Fatma_Yehia)\ **Post date:** [October 27, 2022, 4:11pm UTC](https://community.deeplearning.ai/t/error-with-first-assignment/223128/5 "2022-10-27T16:11:25Z")
What is the difference between both? Yeah, I just begun it this week ---
**Author:** ![ritik5](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@ritik5](https://community.deeplearning.ai/u/ritik5)\ **Post date:** [October 27, 2022, 4:43pm UTC](https://community.deeplearning.ai/t/error-with-first-assignment/223128/6 "2022-10-27T16:43:22Z")
No difference except, () will get printed in first case. I realised that like Enzo mentioned you have error with what you are returning from the function you implemented in above cell. compute\_cost function should return a float value while in your case it is returning an array. If you are not finding how you changed the data type of total\_cost, reload a new notebook and only change the code between `### START CODE HERE ###` and `### END CODE HERE ###` . ---
**Author:** ![Fatma\_Yehia](https://avatars.discourse-cdn.com/v4/letter/f/ecae2f/32.png) [@Fatma\_Yehia](https://community.deeplearning.ai/u/Fatma_Yehia)\ **Post date:** [October 27, 2022, 4:44pm UTC](https://community.deeplearning.ai/t/error-with-first-assignment/223128/7 "2022-10-27T16:44:56Z")
Thanks for explaining it. I am going to try it and see what will go on