ExamAdept

What does the NumPy function numpy.identity(3) generate?

A:

3x3 array with ones on the main diagonal.

B:

3x3 array with ones above the main diagonal.

C:

3x3 array with ones below the main diagonal.

D:

3x3 array with zeros on the main diagonal.

Answer: A

The numpy.identity() function generates an identity matrix with ones on the main diagonal.

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What does the NumPy function numpy.vstack((arr1, arr2)) do?

A:

Stacks arrays vertically.

B:

Stacks arrays horizontally.

C:

Vertically concatenates arrays.

D:

Horizontally concatenates arrays.

Answer: A

The numpy.vstack() function vertically stacks arrays.

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Given a NumPy array arr = np.array([[1, 2, 3], [4, 5, 6]]), how can you extract the second column?

A:

arr[:, 1]

B:

arr[1, :]

C:

arr[1, 1]

D:

arr[:, 2]

Answer: A

The colon : denotes all rows, and 1 specifies the second column.

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Given a NumPy array arr = np.array([[1, 2], [3, 4]]), what does arr.sum(axis=1) calculate?

A:

Sum of all elements in the array.

B:

Sum of elements along the first axis.

C:

Sum of elements along the second axis.

D:

Sum of elements in each row.

Answer: D

The sum() function with axis=1 calculates the sum of elements in each row.

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How can you reverse the order of elements along the first axis of a NumPy array arr?

A:

np.flipud(arr)

B:

np.reverse(arr, axis=0)

C:

np.flip(arr, axis=0)

D:

arr[::-1]

Answer: C

The np.flip() function can be used to reverse the order of elements along a specified axis.

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Questions for: Arrays