need function to compute iterations of element in matrix

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Abdulkareem
Abdulkareem 2014-1-28
评论： Abdulkareem 2014-1-28
hi every body i need matlab function to compute the number of iterations of one elements in matrix just like in excel when u want to compute for example how much the No. 3 occur in some column = counif(a1:a10;"=3") { in excel } is there a function in matlab can do the same thinks
tanks in advance

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AJ von Alt
AJ von Alt 2014-1-28
One approach is to create a logical matrix for the input by comparing it to the target value. You can then sum a row, column, or the whole matrix to get the number of instances, since each instance is indicated by a 1.
% create a 50 x 50 matrix taking integers between 1 and 10
M = randi( 10 , 50 , 50 );
% the value you wish to count instances of
targetVal = 3;
% create logical matrix indicating presence of targetVal at location
isTarget = (M == targetVal);
% Find the number of instances in the matrix
nVals = sum( isTarget(:) );
% Find the number of instances in row 3
nvalsR3 = sum( isTarget(3,:) );
% Find the number of instances in column 12
nvalsC12 = sum( isTarget(:,12) );

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Azzi Abdelmalek
Azzi Abdelmalek 2014-1-28
编辑：Azzi Abdelmalek 2014-1-28
A=[1 2 3;3 0 1;4 5 6;3 1 5]
n1=sum(A(:,1)==3) % number of 3 in the first column
n2=sum(A(:,3)==3) % number of 3 in the third column

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