MATLAB Programming

1 Data Structures
These operations on an empty scalar array return a nonzero value:
A = [];
ndims(A), isnumeric(A), isreal(A), isfloat(A), isempty(A), all(A), prod(A
Using Empty Matrices in Relational Operations
You can use empty matrices in relational operations such as “equal to” (==) or
“greater than” (>) as long as both operands have the same dimensions, or the
nonempty operand is scalar. The result of any relational operation involving
anemptymatrixistheemptymatrix.Evencomparinganemptymatrixfor
equality to itself does not return true, but instead yields an empty matrix:
x = ones(0,3);
y = x;
y == x
ans =
Empty matrix: 0-by-3
Using Empty Matrices in Logical Operations
MATLAB has two distinct types of logical operators:
• Short-circuit (&&, ||) — Used in testing multiple logical conditions (e.g.,
x >= 50 && x < 100) where each condition evaluates to a scalar true
or false.
• Element-wise (&, |) — Performs a logical AND, OR, or NOT on each
element of a matrix or array.
Short-circuit Operations. The rule for operands used in short-circuit
operations is that each operand must be convertible to a logical scalar value.
Because of this rule, empty matrices cannot be used in short-circuit logical
operations. Such operations return an error.
The only exception is in the case where MATLAB can determine the result of
a logical statement without having to evaluate the entire expression. This
is true for the following two statements because the result of the entire
statements are known by considering just the first term:
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