Function to check whether an array contains a duplicate of elements

Question

0 个投票

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)

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the cyclist 2021-7-11

编辑：the cyclist 2021-7-11

Is this a homework assignment? What have you tried yourself? Maybe we can help your learn MATLAB, rather than do your work for you.

Walter Roberson 2021-7-11

Okay, go ahead.

Answer 1

dpb 2021-7-11

编辑：dpb 2021-7-12

0 个投票

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.

dpb 2021-7-12

Yeah, thanks...

Walter Roberson 2023-7-21

Note that this might not behave as expected if there are NaN in the array.