I am writing an easy IF condition. The function is to judge each row of the matrix to be certain vectors. The code is as follows:

  if (compareM(i,:)==[1, 0])||(compareM(i,:) ==[2, 1])
      match_1 = match_1 +1;
  else
      mismatch_1 = mismatch_1 +1;
  end

The error said ''Operands to the || and && operators must be convertible to logical scalar values''.

compareM is a n by 2 matrix and I wonder if the error is made by || operation. Thanks in advance!

• matlab

If you are comparing vectors, not scalar values, you have to use | operator. As a result you get logical vector of element-by-element pairwise comparison. To use it in IF statement you have to convert either each logical statement (then use ||) or the result of | the to scalar with ALL, ANY or other function.

If you want to compare to vectors for equality use ISEQUAL function as

if isequal(compareM(i,:)==[1, 0]) || isequal(compareM(i,:)==[2, 1])

compareM(i, :) evaluates to a 1x2 numeric array, so compareM(i,:)==[1, 0] evaluates to a 1x2 logical array. The same for the expression to the right of the || sign. But you need a single logical value on each side of ||, not a 1x2 array of logical values.

If you want this expression to evaluate to true if both values on the lhs of == are the same as the corresponding elements on the rhs, wrap all() around each side:

all(compareM(i,:)==[1, 0]) || all(compareM(i,:) ==[2, 1])

if ((compareM(i,:)==[1, 0])||(compareM(i,:) ==[2, 1]))
    match_1 = match_1 +1;
else
    mismatch_1 = mismatch_1 +1;
end

Note the outer enclosing parentheses.