# numpy.bincount() in Python

numpy.bincount(arr, weights = None, min_len = 0) : In an array of +ve integers, it counts the occurrence of each element. Each bin value is the occurrence of its index. One can also set the bin size accordingly.
Parameters :

```arr     : [array_like, 1D]Input array, having positive numbers
weights : [array_like, optional]same shape as that of arr
min_len : Minimum number of bins we want in the output array
```

Return :

```Output array with no. of occurrence of index value of bin in input - arr.
Output array, by default is of the length max element of arr + 1.
Here size of the output array would be max(input_arr)+1.
```

Code 1 : Working of bincount() in NumPy

 `# Python Program explaining  ` `# working of numpy.bincount() method ` ` `  `import` `numpy as geek ` ` `  `# 1D array with +ve integers ` `array1 ``=` `[``1``, ``6``, ``1``, ``1``, ``1``, ``2``, ``2``] ` `bin` `=` `geek.bincount(array1) ` `print``(``"Bincount output  : \n "``, ``bin``) ` `print``(``"size of bin : "``, ``len``(``bin``), ``"\n"``) ` ` `  `array2 ``=` `[``1``, ``5``, ``5``, ``5``, ``4``, ``5``, ``5``, ``2``, ``2``, ``2``] ` `bin` `=` `geek.bincount(array2) ` `print``(``"Bincount output  : \n "``, ``bin``) ` `print``(``"size of bin : "``, ``len``(``bin``), ``"\n"``) ` ` `  `# using min_length attribute ` `length ``=` `10` `bin1 ``=` `geek.bincount(array2, ``None``, length) ` `print``(``"Bincount output  : \n "``, bin1) ` ` `  `print``(``"size of bin : "``, ``len``(bin1), ``"\n"``) `

Output :

```Bincount output  :
[0 4 2 0 0 0 1]
size of bin :  7

Bincount output  :
[0 1 3 0 1 5]
size of bin :  6

Bincount output  :
[0 1 3 0 1 5 0 0 0 0]
size of bin :  10

```

Code 2 : We can perform addition as per element with bincount() weight

 `# Python Program explaining  ` `# working of numpy.bincount() method ` ` `  `import` `numpy as geek ` ` `  `# 1D array with +ve integers ` `array2 ``=` `[``10``, ``11``, ``4``, ``6``, ``2``, ``1``, ``9``] ` `array1 ``=` `[``1``, ``3``, ``1``, ``3``, ``1``, ``2``, ``2``] ` ` `  `# array2 : weight ` `bin` `=` `geek.bincount(array1, array2) ` `print``(``"Summation element-wise : \n"``, ``bin``) ` ` `  `#index 0 : 0 ` `#index 1 : 10 + 4 + 2 = 16 ` `#index 2 : 1 + 9 = 10 ` `#index 3 : 11 + 6 = 17 `

Output :

```Summation element-wise :
[  0.  16.  10.  17.]```

References :
https://docs.scipy.org/doc/numpy/reference/generated/numpy.bincount.html#numpy.bincount
.
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