Function to check whether an array contains a duplicate of elements

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I want to write a function that
- Takes as input an array, the value being checked and the starting element of the array where checking for a duplicate should start
- Returns a logical value to indicate whether the array contains a duplicate of the value being checked (stops checking when one is found)
  2 Comments
the cyclist
the cyclist on 11 Jul 2021
Edited: the cyclist on 11 Jul 2021
Is this a homework assignment? What have you tried yourself? Maybe we can help your learn MATLAB, rather than do your work for you.

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Answers (1)

dpb
dpb on 11 Jul 2021
Edited: dpb on 12 Jul 2021
function flag=isduplicate(x,v,ix)
flag=numel(find(x(ix:end)==v))>1;
end
x is vector or if x is array in linear addressing order.
Otherwise, need indexing expression of row, colum, ... for as many dimensions as are greater > 1 in size(x)
If x is floating point, then for robustness, consider ismembertol instead of exact equality or write a tolerance expression.
  3 Comments
Walter Roberson
Walter Roberson on 21 Jul 2023
Note that this might not behave as expected if there are NaN in the array.

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