np.eye() for identity matrices in NumPy - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the function np.eye(n) do in NumPy?

It creates an identity matrix of size n x n. This matrix has 1s on the diagonal and 0s elsewhere.

beginner

How can you create a 4x4 identity matrix using np.eye()?

Use np.eye(4). This returns a 4 by 4 matrix with 1s on the diagonal and 0s elsewhere.

intermediate

What is the difference between np.eye(n) and np.identity(n)?

np.eye(n) can create rectangular matrices by specifying rows and columns, while np.identity(n) only creates square identity matrices of size n x n.

intermediate

How do you create a 3x5 matrix with 1s on the diagonal using np.eye()?

Use np.eye(3, 5). This creates a matrix with 3 rows and 5 columns, with 1s on the diagonal and 0s elsewhere.

intermediate

What parameter in np.eye() controls the diagonal offset?

The k parameter controls which diagonal to place the 1s on. k=0 is the main diagonal, k>0 is above, and k<0 is below the main diagonal.

What does np.eye(3) produce?

A A 3x3 matrix of ones

B A 3x3 matrix of zeros

C A 3x3 identity matrix

D A 3x3 diagonal matrix with twos

np.eye(3) creates a 3x3 identity matrix with 1s on the diagonal and 0s elsewhere.

How do you create a 2x4 matrix with 1s on the diagonal using np.eye()?

A np.eye(2, 4)

B np.eye(4, 2)

C np.eye(2)

D np.eye(4)

np.eye(2, 4) creates a matrix with 2 rows and 4 columns with 1s on the diagonal.

What does the parameter k in np.eye(n, m, k) do?

A Sets the diagonal offset where 1s are placed

B Sets the number of rows

C Sets the number of columns

D Sets the data type

The k parameter shifts the diagonal where 1s appear: 0 is main diagonal, positive is above, negative is below.

Which function only creates square identity matrices?

A np.zeros()

B np.identity()

C np.eye()

D np.ones()

np.identity() creates only square identity matrices, while np.eye() can create rectangular ones.

What will np.eye(3, 3, k=1) produce?

A A 3x3 matrix with 1s below the main diagonal

B A 3x3 identity matrix

C A 3x3 matrix of zeros

D A 3x3 matrix with 1s on the diagonal above the main diagonal

Setting k=1 places 1s on the diagonal just above the main diagonal.

Explain how to create an identity matrix and how to adjust its size and shape using np.eye().

Think about rows, columns, and diagonal offset.

Describe the difference between np.eye() and np.identity().

Focus on shape flexibility.