MATLAB 並不需要任何類型的聲明或維度報表。 MATLAB 每當遇到一個新的變量名稱，創建變量，並分配適當的內存空間。

如果變量已經存在，則MATLAB替換以新的內容的原始內容，並分配新的存儲空間，在必要的情況下。

例如，

Total = 42

上述語句創建了一個名為“Total” 的 1-1 矩陣存儲值42。

MATLAB中可用的數據類型

MATLAB 提供15個基本數據類型。每種數據類型的數據存儲在矩陣或陣列的形式。這個矩陣的大小或陣列是一個最低 0-0，這可以長大為任何規模大小的矩陣或數組。

下表顯示了在 MATLAB 中最常用的數據類型：

數據類型	描述
int8	8-bit signed integer
uint8	8-bit unsigned integer
int16	16-bit signed integer
uint16	16-bit unsigned integer
int32	32-bit signed integer
uint32	32-bit unsigned integer
int64	64-bit signed integer
uint64	64-bit unsigned integer
single	single precision numerical data
double	double precision numerical data
logical	logical values of 1 or 0, represent true and false respectively
char	character data (strings are stored as vector of characters)
cell array	array of indexed cells, each capable of storing an array of a different dimension and data type
structure	C-like structures, each structure having named fields capable of storing an array of a different dimension and data type
function handle	yiibaier to a function
user classes	objects constructed from a user-defined class
java classes	objects constructed from a Java class

例子

創建一個腳本文件，用下麵的代碼：

str = 'Hello World!'
n = 2345
d = double(n)
un = uint32(789.50)
rn = 5678.92347
c = int32(rn)

上麵的代碼編譯和執行時，它會產生以下結果：

str =
Hello World!
n =
   2345
d =
   2345
un =
   790
rn =
   5.6789e+03
c =
   5679

數據類型轉換

MATLAB 提供各種函數，用於從一種數據類型轉換到另一種。下表顯示的數據類型轉換函數：

函數	目的/作用
char	Convert to character array (string)
int2str	Convert integer data to string
mat2str	Convert matrix to string
num2str	Convert number to string
str2double	Convert string to double-precision value
str2num	Convert string to number
native2unicode	Convert numeric bytes to Unicode characters
unicode2native	Convert Unicode characters to numeric bytes
base2dec	Convert base N number string to decimal number
bin2dec	Convert binary number string to decimal number
dec2base	Convert decimal to base N number in string
dec2bin	Convert decimal to binary number in string
dec2hex	Convert decimal to hexadecimal number in string
hex2dec	Convert hexadecimal number string to decimal number
hex2num	Convert hexadecimal number string to double-precision number
num2hex	Convert singles and doubles to IEEE hexadecimal strings
cell2mat	Convert cell array to numeric array
cell2struct	Convert cell array to structure array
cellstr	Create cell array of strings from character array
mat2cell	Convert array to cell array with potentially different sized cells
num2cell	Convert array to cell array with consistently sized cells
struct2cell	Convert structure to cell array

測定的數據類型

MATLAB 提供各種函數標識數據類型的變量。

下表提供了確定一個變量的數據類型的函數：

函數	目的/作用
is	Detect state
isa	Determine if input is object of specified class
iscell	Determine whether input is cell array
iscellstr	Determine whether input is cell array of strings
ischar	Determine whether item is character array
isfield	Determine whether input is structure array field
isfloat	Determine if input is floating-yiibai array
ishghandle	True for Handle Graphics object handles
isinteger	Determine if input is integer array
isjava	Determine if input is Java object
islogical	Determine if input is logical array
isnumeric	Determine if input is numeric array
isobject	Determine if input is MATLAB object
isreal	Check if input is real array
isscalar	Determine whether input is scalar
isstr	Determine whether input is character array
isstruct	Determine whether input is structure array
isvector	Determine whether input is vector
class	Determine class of object
validateattributes	Check validity of array
whos	List variables in workspace, with sizes and types

例子

創建一個腳本文件，用下麵的代碼：

x = 3
isinteger(x)
isfloat(x)
isvector(x)
isscalar(x)
isnumeric(x)
 
x = 23.54
isinteger(x)
isfloat(x)
isvector(x)
isscalar(x)
isnumeric(x)
 
x = [1 2 3]
isinteger(x)
isfloat(x)
isvector(x)
isscalar(x)
 
x = 'Hello'
isinteger(x)
isfloat(x)
isvector(x)
isscalar(x)
isnumeric(x)

當運行該文件，它會產生以下結果：

x =
     3
ans =
     0
ans =
     1
ans =
     1
ans =
     1
ans =
     1
x =
   23.5400
ans =
     0
ans =
     1
ans =
     1
ans =
     1
ans =
     1
x =
     1     2     3
ans =
     0
ans =
     1
ans =
     1
ans =
     0
x =
Hello
ans =
     0
ans =
     0
ans =
     1
ans =
     0
ans =
     0