count rows in matrix ?

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Rakesh Praveen
Rakesh Praveen on 7 Nov 2011
hey, i want to know is there a way to get how many rows are there in a given matrix. like for example when we say 'length(A)' it can give number of columns in a matrix(A), likewise can we know about number of rows ?
thank you.
morteza HEIDARI
morteza HEIDARI on 15 Aug 2017
Edited: morteza HEIDARI on 15 Aug 2017
If for example your matrix is A, you can use : size(A,1) for number of rows. size(A,2) for number of columns. Also there are some other ways like : length ( A(:,1) ) for number of rows.

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Accepted Answer

Oleg Komarov
Oleg Komarov on 7 Nov 2011
Edited: MathWorks Support Team on 4 Nov 2020
The following documentation provides more information on 'size' function:
Starting in R2020b, you can also use "height" and "width" function to count rows and columns of a matrix respectively.
For example:
A=rand(3,2); %Defining a matrix;
count_rows=height(A); %Computes number of rows in A
count_columns=width(A); %Computes number of columns in A
For more information on "height" and "width" functions, please refer to the following documentation:
Pooja on 22 Sep 2014
It workd for me also. Thankyou Oleg Komarov

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More Answers (5)

Ashutosh Kumar
Ashutosh Kumar on 22 Jul 2016
length(A) gives you maximum out of the matrix made by calling the size,so it doesn't give you column(A) and for calling column(A) you need size(A,2) and for row you need size(A,1) suppose you have a 5*4 matrix then length(A) will give you 5 number of rows not 4...Hope that will help others I myself used length(A) and ended up making a wrong code and took me 2 hours to do it right

Image Analyst
Image Analyst on 7 Nov 2011
For a 2D matrix:
[rows columns] = size(array2D);
or, in general,
sizeOfMatrix = size(yourMatrix);
  1 Comment
Rakesh Praveen
Rakesh Praveen on 7 Nov 2011
thank u very much image analyst

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Thulitha Theekshana
Thulitha Theekshana on 17 Jul 2019
I think the best way is to use size(x,y) function.
ex: if you want to get the height, size(matrix_name, 1). Here the second variable denotes the dimensioin you need to measure. From one it means the number of rows or the first dimension. From 2 it means the number of columns or the length. So I think you get the idea,

Gaganjyoti Baishya
Gaganjyoti Baishya on 20 Jun 2020
It's simple. You can see the size of the first column, that will be the rows in matrix.
rows = size(myMatrix, 1); % first row length

Anurag Pratap Singh
Anurag Pratap Singh on 25 Jun 2020
Hi Rakesh
For counting the number of rows in a matrix you can use the size funtction and pass your matrix in it
[NumRows NumCols]=size(your_matrix);
The first output is the Number of rows .
Thank you

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