| MATLAB Function Reference | |
Convert numeric values to logical
Syntax
K = logical(A)
Description
K = logical(A)
returns an array that can be used for logical indexing or logical tests.
A(B), where B is a logical array, returns the values of A at the indices where the real part of B is nonzero. B must be the same size as A.
Remarks
Most arithmetic operations remove the logicalness from an array. For example, adding zero to a logical array removes its logical characteristic. A = +A is the easiest way to convert a logical double array, A, to a strictly numeric double array.
Logical arrays are also created by the relational operators (==,<,>,~, etc.) and functions like any, all, isnan, isinf, and isfinite.
Examples
Given A = [1 2 3; 4 5 6; 7 8 9], the statement B = logical(eye(3)) returns a logical array
B = 1 0 0 0 1 0 0 0 1
which can be used in logical indexing that returns A's diagonal elements:
A(B)
ans =
1
5
9
However, attempting to index into A using the numeric array eye(3) results in:
A(eye(3)) ??? Index into matrix is negative or zero.
See Also
| | log2 | loglog | |