Question about finding the number of times an element appears in an array
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Can someone explain why/how this code works in creating an array B which corresponds to the number of each integer from 1-9 in array A?
c=[1:9]
B=sum(A(:)==c, 1)
2 commentaires
Rik
le 4 Nov 2021
Combining unique with histc (or histcounts) might be either safer, or more performant for larger arrays than this setup.
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Chris
le 4 Nov 2021
Modifié(e) : Chris
le 4 Nov 2021
A = randi(9,2)
A(:) formats A in a column vector.
A(:)
A(:)==c compares the column to each element of c (possible because the dimensions of a and c are orthogonal), returning an nx9 matrix with ones where the comparison is true.
A(:)==1:9
Summing across dimension 1 (the default):
B=sum(A(:)==1:9)
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