using "&" with logical array

oN is a array Logical

col is array Logical

why is not correct using &?

K>> class(oN)

ans =

'logical'

K>> class(col)

ans =

'logical'

Answer 1

[Stephen23]

"why is not correct using &?"

Who says that it is not "correct" ? What you show is not a code error (underlined in red), it is a recommendation (underlined in orange)

Benefits:

• For scalar values && is (in general) faster than & because it only evaluates the right argument if the left argument is TRUE.
• Defensive programming: by using && you assert that its arguments are scalar. If later they are erroneously not scalar then && will stop with an error (rarher than continuing in some unknown state).
• Clarity to the reader

If you want to ignore this recommendation then right-click and select one of the "ignore" options.

[Luca Re]

The array is a logical type so the correct use of the operator is to use the "&" for logical operations.

"&&" if they are scalars but this is not the data type in question

[Stephen23]

"The array is a logical type so the correct use of the operator is to use the "&" for logical operations.

You just invented that rule yourself: there is no rule saying that scalar values must use &.

In contrast the static code parser is written by the people who actually develop MATLAB.

""&&" if they are scalars but this is not the data type in question"

MATLAB does not have a "scalar" data type, they are all arrays:

https://www.mathworks.com/help/matlab/matlab_prog/fundamental-matlab-classes.html

Most likely the data in question is scalar: assuming that k is a scalar subscript then both of the arguments to && will be scalar, and the recommendation is completely appropriate. That is most likely what the static parser has detected. Your invention of non-existent data types and non-existent rules does not help you.

Question: what size do oN(k) and col(k) have?

[Luca Re]

ok thank..i understand