MATLAB Basics

Basics

• MATLAB is designed around double precision, complex numbers, and arrays
• End any value-producing statement with ; to suppress its result display, especially in scripts
• The comment marker is %
  • %{...%} for multi-line comments
• MATLAB is insensitive to indentation; the end of a block is marked by end

Numeric Constants

Constant	Description
pi	$\pi$
eps	Floating-point relative precision $2.2204e\text{-}16$
i, j	Imaginary unit $\sqrt{-1}$
inf, Inf	Infinity, e.g. $\frac{1}{0}$
nan, NaN	Indeterminate (not a number), e.g. $\frac{0}{0}$
intmax	Largest representable integer $2147483647$
intmin	Smallest representable integer $-2147483648$
realmax	Largest representable positive real $1.7977e\text{+}308$
realmin	Smallest representable positive real $2.2251e\text{-}308$

Keywords

Keyword	Usage
break
case
catch
classdef
continue
else
elseif
end
for
function
global
if
otherwise
parfor
persistent
return
spmd
switch
try
while

Variables

Like Python, MATLAB does not require variable declarations or type annotations.

Variable Naming Rules

1. Must consist only of letters, digits, and underscores, and must begin with a letter
2. Case-sensitive
3. Length must not exceed 31 characters
4. Must not be a keyword
5. May reuse a constant or function name
   • After such reuse, the name no longer refers to the original constant or function

Validating Variable Names

• Use Matlab Functions - iskeyword to check whether a name is a keyword
• Use Matlab Functions - exist to check whether a name is already in use as a variable, function, file, or folder

Predefined Variables

Variable	Description
ans	Default variable that receives a result when no assignment is given
nargin	Number of input arguments actually passed to a function
nargout	Number of output arguments actually requested