# numpy.mean() in Python

• Difficulty Level : Basic
• Last Updated : 28 Nov, 2018

`numpy.mean(arr, axis = None)` : Compute the arithmetic mean (average) of the given data (array elements) along the specified axis.

Parameters :
arr : [array_like]input array.
axis : [int or tuples of int]axis along which we want to calculate the arithmetic mean. Otherwise, it will consider arr to be flattened(works on all
the axis). axis = 0 means along the column and axis = 1 means working along the row.
out : [ndarray, optional]Different array in which we want to place the result. The array must have the same dimensions as expected output.
dtype : [data-type, optional]Type we desire while computing mean.

Results : Arithmetic mean of the array (a scalar value if axis is none) or array with mean values along specified axis.

Code #1:

 `# Python Program illustrating ``# numpy.mean() method ``import` `numpy as np``   ` `# 1D array ``arr ``=` `[``20``, ``2``, ``7``, ``1``, ``34``]`` ` `print``(``"arr : "``, arr) ``print``(``"mean of arr : "``, np.mean(arr))``  `

Output :

```arr :  [20, 2, 7, 1, 34]
mean of arr :  12.8
```

Code #2:

 `# Python Program illustrating ``# numpy.mean() method   ``import` `numpy as np``   ` ` ` `# 2D array ``arr ``=` `[[``14``, ``17``, ``12``, ``33``, ``44``],  ``       ``[``15``, ``6``, ``27``, ``8``, ``19``], ``       ``[``23``, ``2``, ``54``, ``1``, ``4``, ]] ``   ` `# mean of the flattened array ``print``(``"\nmean of arr, axis = None : "``, np.mean(arr)) ``   ` `# mean along the axis = 0 ``print``(``"\nmean of arr, axis = 0 : "``, np.mean(arr, axis ``=` `0``)) ``  ` `# mean along the axis = 1 ``print``(``"\nmean of arr, axis = 1 : "``, np.mean(arr, axis ``=` `1``))`` ` `out_arr ``=` `np.arange(``3``)``print``(``"\nout_arr : "``, out_arr) ``print``(``"mean of arr, axis = 1 : "``, ``      ``np.mean(arr, axis ``=` `1``, out ``=` `out_arr))`

Output :

```mean of arr, axis = None :  18.6

mean of arr, axis = 0 :  [17.33333333  8.33333333 31.         14.         22.33333333]

mean of arr, axis = 1 :  [24.  15.  16.8]

out_arr :  [0 1 2]
mean of arr, axis = 1 :  [24 15 16]
```

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