# numpy.sum() in Python

`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]]```

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