Number of counts in matrix

How to count the number of individual elements in a matrix using matlab? I mean the number of times individual elements appear.

Answer 1

[Voss]

You can use nnz.

Example:

A = [1 1 2; 2 1 2; 3 1 1]

A = 3x3

1 1 2 2 1 2 3 1 1

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nnz(A == 1) % number of times 1 appears in A

ans = 5

nnz(A == 2) % number of times 2 appears in A

ans = 3

nnz(A == 3) % number of times 3 appears in A

ans = 1

[Prince]

Thank you but I need a code to do everything at the same time. It is a 150x150 matrix and I cannot count them individually.

[Voss]

You're welcome!

Here's one way to do it all at once:

A = randi([1,10],15,15)

A = 15x15

6 8 9 5 1 1 1 10 6 10 1 2 6 10 4 2 9 7 1 8 2 5 4 7 7 3 10 6 4 5 3 5 9 6 10 10 9 9 10 2 1 6 4 6 3 5 7 1 5 2 7 7 2 2 3 7 3 6 10 5 2 4 2 6 9 10 8 7 1 6 3 3 10 1 10 6 8 4 4 9 8 5 9 1 2 4 5 1 3 2 1 3 10 10 4 6 1 6 4 8 3 7 2 3 1 10 9 10 6 6 6 4 10 7 8 7 9 9 8 2 1 3 2 8 6 5 2 6 9 10 6 9 5 8 2 9 6 7 4 6 8 5 5 4 10 9 6 3 1 7

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[g,value] = findgroups(A(:));
count = groupsummary(A(:),g,'nnz');

result = table(value,count)

result = 10x2 table
    value    count
    _____    _____

      1       24  
      2       27  
      3       19  
      4       22  
      5       23  
      6       30  
      7       21  
      8       16  
      9       21  
     10       22  

[Prince]

It worked. Thank you so much

[Voss]

Great! You're welcome!

Answer 2

[Steven Lord]

Use histcounts with unique (or uniquetol) to generate the bins. You will need to add one more bin at the end since the last bin includes both its edges (unlike the other bins, which only include their left edges.) I would use inf as the right-most end of that last bin.