CODEWITHSUNDEEP
arraysmatlab
zahra
zahra

Reputation: 11

how can I divide a Matlab array to different regions?

I have an array of [1 1 1 1 2 2 2 3 2 3 3 3 1 1 2 2 ]. how can I divide it to ranges which shows same numbers in one array in Matlab? I want to make matrix B which is:

B(1) = [1 1 1 1]; 
B(2) = [2 2 2] ; 
B(3)= [3 3 3];
B(4) = [1 1];
B(5) = [2 2].

Upvotes: 1

Views: 110

Answers (2)

gnovice
gnovice

Reputation: 125854

This is basically run-length encoding, the difference being you want to break the vector up into each string of repeated values instead of producing pairs of [value, nRepeats] as is typically desired. Since your strings of repeated values have different lengths, you'll need to store them in a cell array. Here's one way to do it, using diff, find, and mat2cell:

A = [1 1 1 1 2 2 2 3 2 3 3 3 1 1 2 2];
nReps = diff([0 find(diff(A)) numel(A)]);
B = mat2cell(A, 1, nReps);

This works by first computing the element-wise differences in A with diff. Anywhere there is a non-zero result represents a change in the value, and the index location of these non-zeroes are found with find. Padding the ends with 0 and the length of vector A and applying diff again gives us the length of each string of values. The original vector A is then broken up into a cell array using mat2cell and these lengths.

Upvotes: 3

cyrusthegreat
cyrusthegreat

Reputation: 21

Set one variable as the original number, so a = array[1], then test if the next value is the same as the previous, have a counter variable attached to this. Once is it not, load into array B, and change value of that variable and do it again.

make B a 2d array

Or, look into the unqie function of matlab and use the indexes to fill B.

Upvotes: 0

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