How to control number of element or number of unique element in Matrix?

x= [15 30 45 60 -45 -30 0 90 15 30 45 60 -45 -30 0 90 15 45 60 -45 -30 0];%Initial guess

 a = unique(x);   % unique elements
 [countingofangles, Thetaangles]  = hist(x,unique(x));   % Unique Theta and counting of theta
  A = Thetaangles;     % Theta used in initial guess x
 c = countingofangles;     %No of theta used in initial guess x

y = repmat(x,numel(a),1);    %repeat x matrix
y(:,end) = a';           %replace last column by transpose(a)

output

 A =

   -45   -30     0    15    30    45    60    90     %Theta used in x

 c =

     3     3     3     3     2     3     3     2     %Number of theta corresponding to A

 y =

    15    30    45    60   -45   -30     0    90    15    30    45    60   -45   -30     0    90    15    45    60   -45   -30   -45
    15    30    45    60   -45   -30     0    90    15    30    45    60   -45   -30     0    90    15    45    60   -45   -30   -30
    15    30    45    60   -45   -30     0    90    15    30    45    60   -45   -30     0    90    15    45    60   -45   -30     0
    15    30    45    60   -45   -30     0    90    15    30    45    60   -45   -30     0    90    15    45    60   -45   -30    15
    15    30    45    60   -45   -30     0    90    15    30    45    60   -45   -30     0    90    15    45    60   -45   -30    30
    15    30    45    60   -45   -30     0    90    15    30    45    60   -45   -30     0    90    15    45    60   -45   -30    45
    15    30    45    60   -45   -30     0    90    15    30    45    60   -45   -30     0    90    15    45    60   -45   -30    60
    15    30    45    60   -45   -30     0    90    15    30    45    60   -45   -30     0    90    15    45    60   -45   -30    90

I want to eliminate/delete that row which contains no of theta/counting of theta/angles(15,30, 45 etc) less than 3

Answer 1

[the cyclist]

I'm not 100% certain I understand your question, but I think this does what you want:

y(c<3,:) = [];

[Triveni]

Thanks very much sir

[Triveni]

It's not working for all cases

 x= [90 90 -45 0 0 45 45 0 -45];%Initial guess
a = unique(x);   % unique elements
 [countingofangles, Thetaangles]  = hist(x,unique(x));   % Unique Theta and counting of theta
  A = Thetaangles;     % Theta used in initial guess x
 c = countingofangles;     %No of theta used in initial guess x
 y = repmat(x,numel(a),1);    %repeat x matrix
y(:,end) = a';           %replace last column by transpose(a)
y(c<3,:) = [];

you find only two theta of 90 and 45 ...-45 theta only 1 I need empty array in this case.

[the cyclist]

In your original question, you said "I want to eliminate/delete that row which contains no of theta/counting of theta/angles(15,30, 45 etc) less than 3".

You are the one who calculated the value of c, which is [2 3 2 2]. I eliminated the rows of y for which c was less than 3. I'm not sure which part you are saying is wrong.

[Triveni]

I simply say sorry... Sir you try to help lot as possible.

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency

[Image Analyst]

Generally you would NOT want to throw out bins at various places in the histogram. It would make it very difficult and deceiving to try to use the arrays afterwards.

[Triveni]

Lot of thanks Sir, Actually i developing an algorithm, that's why i need this type of array. Lastly please help me once again, I have a Matrix.

 y =[ 90    90   -45     0     0    45    45     0   -45    15    30   -30    75   -45    75   -75
         90    90   -45     0     0   -45   -45     0   -45    15    30   -30    75   -45    75   -45
         90    90   -45     0     0    45    45     0   -45    15    30   -30    75   -45    75   -30
         90    90   -45     0     0    45    45     0   -45    15    30   -30    75   -45    75     0
         90    90   -45     0     0    45    45     0   -45    15    30   -30    75   -45    75    15
         90    90   -45     0     0    45    45     0   -45    15    30   -30    75   -45    75    30
         90    90    45     0     0    45    45     0    45    15    30   -30    75    45    75    45
         90    90   -45     0     0    45    45     0   -45    15    30   -30    75   -45    75    75
         90    90   -45     0     0    45    45     0   -45    15    30   -30    75   -45    75    90];

unique(y) =9;

Sir tell me to count unique value in every row, and if unique elements in row less than 9, should be deleted. I hope you would do it for me.