numpy.eye

numpy.eye(N, M=None, k=0, dtype=<type 'float'>)

Return a 2-D array with ones on the diagonal and zeros elsewhere.

Parameters:

N : int

Number of rows in the output.

M : int, optional

Number of columns in the output. If None, defaults to N.

k : int, optional

Index of the diagonal: 0 refers to the main diagonal, a positive value refers to an upper diagonal, and a negative value to a lower diagonal.

dtype : dtype, optional

Data-type of the returned array.

Returns:

I : ndarray (N,M)

An array where all elements are equal to zero, except for the k-th diagonal, whose values are equal to one.

See also

diag

Return a diagonal 2-D array using a 1-D array specified by the user.

Examples

>>> np.eye(2, dtype=int)
array([[1, 0],
       [0, 1]])
>>> np.eye(3, k=1)
array([[ 0.,  1.,  0.],
       [ 0.,  0.,  1.],
       [ 0.,  0.,  0.]])