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,

Yes, it is. I just search for how can I solve it since I don’t know any experience with python before

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) course.

What is the difference between both?

Yeah, I just begun it this week

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 ###`

.

Thanks for explaining it. I am going to try it and see what will go on