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How can I have matlab identify if a specific element is repeated a specific number of times?

Asked by George on 12 Dec 2012

Lets say a I have a 10 by 10 matrix with a random combination of numbers. So I want MATLAB to check a specific number is repeated a specific times. For example, what can I type if I want MATLAB to check if the number 1 is repeated 3 times in the 10 by 10 matrix?

0 Comments

George

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2 Answers

Answer by Walter Roberson on 12 Dec 2012
sum(A(:) == 1) == 3

2 Comments

George on 13 Dec 2012

So if I would like to see if the number 2 is in the matrix 3 times would I type

sum(A(:)==2)==3

Walter Roberson on 13 Dec 2012

Yes,

sum(A(:) == NumberToTestFor) == CountRequired
Walter Roberson
Answer by Muruganandham Subramanian on 12 Dec 2012
Edited by Muruganandham Subramanian on 12 Dec 2012

try this:

 find(A==1)

If you would like to know more,

>>help find

3 Comments

Walter Roberson on 12 Dec 2012

That does not check to see if the element was repeated the correct number of times.

Muruganandham Subramanian on 12 Dec 2012

If you need to check for no.of times, assign a variable

   c=find(A==1)
   size(c)
Walter Roberson on 12 Dec 2012

You can apply size() to an expression

size(find(A==1))

size() is, either way, going to return a vector of dimensions. Which of those elements should George check? Will the answer vary in newer MATLAB versions which are changing the rules about whether various functions return row outputs or column outputs?

Muruganandham Subramanian

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