In an array of +ve integers, the numpy.bincount() method counts the occurrence of each element. Each bin value is the occurrence of its index. One can also set the bin size accordingly.
Syntax :
numpy.bincount(arr, weights = None, min_len = 0)
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 integersarray1 = [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 attributelength = 10bin1 = 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 integersarray2 = [10, 11, 4, 6, 2, 1, 9]array1 = [1, 3, 1, 3, 1, 2, 2] # array2 : weightbin = 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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