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+--- Thread: append list to empty array (/thread-24149.html)
append list to empty array - SchroedingersLion - Feb-02-2020
Hello guys,
I would like to know why the following does not give me an Nx7 array.
X_y_disch = np.empty((0,7), float)
for keys in B1_B2:
X_y_disch = np.append(X_y_disch, [[k for k in B1_B2[keys]["Discharge-Model"].values()] + [B1_B2[keys]["Cycle Life"][0,0]]])where B1_B2 is a nested dictionary. Each k in the "k for k" loop yields a float, i.e. [k for k in B1_B2[keys]["Discharge-Model"].values()]is a list of N-1 floats.
B1_B2[keys]["Cycle Life"][0,0]yields a float as well.
I obtain a 1d array, instead of N x 7.
RE: append list to empty array - SchroedingersLion - Feb-02-2020
I found the solution: One has to specify axis=0 in order to get what I want, otherwise the arrays are flattened before appending is performed.
X_y_disch = np.append(X_y_disch, [[k for k in B1_B2[keys]["Discharge-Model"].values()] + [B1_B2[keys]["Cycle Life"][0,0]]], axis=0)