# NumPy: eye() function

## eye() function

The eye() function is used to create a 2-D array with ones on the diagonal and zeros elsewhere.

Syntax:

`numpy.eye(N, M=None, k=0, dtype=<class 'float'>, order='C')` Version: 1.15.0

Parameter:

Name Description Required /
Optional
N Number of rows in the output. Required
M Number of columns in the output. If None, defaults to N. optional
k Index of the diagonal: 0 (the default) refers to the main diagonal, a positive value refers to an upper diagonal, and a negative value to a lower diagonal. optional
dtype Data-type of the returned array. optional
order Whether the output should be stored in row-major (C-style) or column-major (Fortran-style) order in memory optional

Return value:

[ndarray of shape (N,M)] An array where all elements are equal to zero, except for the k-th diagonal, whose values are equal to one.

Example: NumPy.eye()

``````>>> import numpy as np
>>> np.eye(2)
array([[ 1.,  0.],
[ 0.,  1.]])
>>> np.eye(2,3)
array([[ 1.,  0.,  0.],
[ 0.,  1.,  0.]])
>>> np.eye(3, 3)
array([[ 1.,  0.,  0.],
[ 0.,  1.,  0.],
[ 0.,  0.,  1.]])
>>> ``````

Pictorial Presentation:   Example: NumPy.eye() where data type is int

``````>>> import numpy as np
>>> np.eye(2, dtype=int)
array([[1, 0],
[0, 1]])
>>> np.eye(2,2,  dtype=int)
array([[1, 0],
[0, 1]])
>>> np.eye(2,2,  dtype=float)
array([[ 1.,  0.],
[ 0.,  1.]])
>>> ``````

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