Related Articles
numpy.sum() in Python
• Last Updated : 03 Apr, 2020

`numpy.sum(arr, axis, dtype, out)` : This function returns the sum of array elements over the specified axis.

Parameters :
arr : input array.
axis : axis along which we want to calculate the sum value. 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 : Different array in which we want to place the result. The array must have same dimensions as expected output. Default is None.
initial : [scalar, optional] Starting value of the sum.

Return : Sum of the array elements (a scalar value if axis is none) or array with sum values along the specified axis.

Code #1:

 `# Python Program illustrating ``# numpy.sum() method``import` `numpy as np ``      ` `# 1D array ``arr ``=` `[``20``, ``2``, .``2``, ``10``, ``4``]  ``  ` `print``(``"\nSum of arr : "``, np.``sum``(arr)) ``  ` `print``(``"Sum of arr(uint8) : "``, np.``sum``(arr, dtype ``=` `np.uint8)) ``print``(``"Sum of arr(float32) : "``, np.``sum``(arr, dtype ``=` `np.float32))``  ` `print` `(``"\nIs np.sum(arr).dtype == np.uint : "``, ``       ``np.``sum``(arr).dtype ``=``=` `np.uint) `` ` `print` `(``"Is np.sum(arr).dtype == np.float : "``, ``       ``np.``sum``(arr).dtype ``=``=` `np.``float``) `

Output:

```Sum of arr :  36.2
Sum of arr(uint8) :  36
Sum of arr(float32) :  36.2

Is np.sum(arr).dtype == np.uint :  False
Is np.sum(arr).dtype == np.uint :  True
```

Code #2:

 `# Python Program illustrating ``# numpy.sum() method``import` `numpy as np ``      ` `# 2D array ``arr ``=` `[[``14``, ``17``, ``12``, ``33``, ``44``],   ``       ``[``15``, ``6``, ``27``, ``8``, ``19``],  ``       ``[``23``, ``2``, ``54``, ``1``, ``4``,]]  ``  ` `print``(``"\nSum of arr : "``, np.``sum``(arr)) ``  ` `print``(``"Sum of arr(uint8) : "``, np.``sum``(arr, dtype ``=` `np.uint8)) ``print``(``"Sum of arr(float32) : "``, np.``sum``(arr, dtype ``=` `np.float32))``  ` `print` `(``"\nIs np.sum(arr).dtype == np.uint : "``, ``                 ``np.``sum``(arr).dtype ``=``=` `np.uint) `` ` `print` `(``"Is np.sum(arr).dtype == np.uint : "``, ``              ``np.``sum``(arr).dtype ``=``=` `np.``float``) `

Output:

```Sum of arr :  279
Sum of arr(uint8) :  23
Sum of arr(float32) :  279.0

Is np.sum(arr).dtype == np.uint :  False
Is np.sum(arr).dtype == np.uint :  False
```

Code #3:

 `# Python Program illustrating ``# numpy.sum() method ``      ` `import` `numpy as np ``      ` `# 2D array  ``arr ``=` `[[``14``, ``17``, ``12``, ``33``, ``44``],   ``       ``[``15``, ``6``, ``27``, ``8``, ``19``],  ``       ``[``23``, ``2``, ``54``, ``1``, ``4``,]]  ``  ` `print``(``"\nSum of arr : "``, np.``sum``(arr)) ``print``(``"Sum of arr(axis = 0) : "``, np.``sum``(arr, axis ``=` `0``)) ``print``(``"Sum of arr(axis = 1) : "``, np.``sum``(arr, axis ``=` `1``))`` ` `print``(``"\nSum of arr (keepdimension is True): \n"``,``      ``np.``sum``(arr, axis ``=` `1``, keepdims ``=` `True``))`

Output:

```Sum of arr :  279
Sum of arr(axis = 0) :  [52 25 93 42 67]
Sum of arr(axis = 1) :  [120  75  84]

Sum of arr (keepdimension is True):
[
[ 75]
[ 84]]```

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes arrow_drop_up