# MATLAB数据类型

MATLAB 并不需要任何类型的声明或维度报表。 MATLAB 每当遇到一个新的变量名称，创建变量，并分配适当的内存空间。

`Total = 42`

## MATLAB中可用的数据类型

MATLAB 提供15个基本数据类型。每种数据类型的数据存储在矩阵或阵列的形式。这个矩阵的大小或阵列是一个最低 0-0，这可以长大为任何规模大小的矩阵或数组。

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

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

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

## 数据类型转换

MATLAB 提供各种函数，用于从一种数据类型转换到另一种。下表显示的数据类型转换函数：

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

## 测定的数据类型

MATLAB 提供各种函数标识数据类型的变量。

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

`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)`

```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```