Np.where in C2_W1_Assignment

Hi ,

in one of the last sections of the practice lab, we use

   errors = np.where(y != Yhat)

to get indexes where y and Yhat are different. But if I print “errors”, it says for index 142 and 0 they are different values. If I check for y[0] and Yhat[0], they have the same value. Does somebody know, why thats the case ?

I guess you wanted to use np.argwhere instead?

The code is not from me. It was already there, only to execute. Im only confused why it gives the value 0 back, when y[0] and Yhat[0] are not different. For 142 they are different

I see. 142 is a row index, and 0 is a column index. You need a row index and a column index to identify an array element in a 2D array. Perhaps try to think about how the following line works?

plt.title(f"{y[random_index,0]}, {Yhat[random_index, 0]}")

You may also want to go through the lines in your screenshot, line by line.

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Thank you, that makes sense :slight_smile:

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