# Find unique rows in a NumPy array

• Difficulty Level : Easy
• Last Updated : 02 Sep, 2020

In this article we will discuss how to find unique rows in a NumPy array. To find unique rows in a NumPy array we are using numpy.unique() function of NumPy library.

Syntax : numpy.unique(ar, return_index=False, return_inverse=False, return_counts=False, axis=None)

Now, let’s see an example:

Example 1:

## Python3

 `# import library``import` `numpy as np`` ` `# Create a 2D numpy array``arr2D ``=` `np.array([[``11``, ``11``, ``12``, ``11``],``                     ``[``13``, ``11``, ``12``, ``11``],``                     ``[``16``, ``11``, ``12``, ``11``],``                     ``[``11``, ``11``, ``12``, ``11``]])`` ` `print``(``'Original Array :'` `,``      ``arr2D, sep ``=` `'\n'``)`` ` `# Get unique rows from``# complete 2D-array by ``# passing axis = 0 in ``# unique function along``# with 2D-array``uniqueRows ``=` `np.unique(arr2D, ``                       ``axis ``=` `0``)`` ` `# print the output result``print``(``'Unique Rows:'``,``      ``uniqueRows, sep ``=` `'\n'``)`

Output:

```Original Array :
[[11 11 12 11]
[13 11 12 11]
[16 11 12 11]
[11 11 12 11]]
Unique Rows:
[[11 11 12 11]
[13 11 12 11]
[16 11 12 11]]
```

Example 2:

## Python3

 `# import library``import` `numpy as np`` ` `# create 2d numpy array``array ``=` `np.array([[``1``, ``2``, ``3``, ``4``],``                  ``[``3``, ``2``, ``4``, ``1``],``                  ``[``6``, ``8``, ``1``, ``2``]])`` ` `print``(``"Original array: \n"``,``      ``array)`` ` `# Get unique rows from``# complete 2D-array by ``# passing axis = 0 in ``# unique function along``# with 2D-array``uniqueRows ``=` `np.unique(array, ``                       ``axis ``=` `0``)`` ` `# print the output result``print``(``'Unique Rows :'``,``      ``uniqueRows,``      ``sep ``=` `'\n'``)`

Output:

```Original array:
[[1 2 3 4]
[3 2 4 1]
[6 8 1 2]]
Unique Rows :
[[1 2 3 4]
[3 2 4 1]
[6 8 1 2]]
```

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