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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。# [! X" |4 G" I/ C2 `& Z! H- q3 v
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如果变量已经存在,则MATLAB替换以新的内容的原始内容,并分配新的存储空间,在必要的情况下。- }& o. B8 M: P: _
! a2 y& y2 R# O8 P 例如,
: C: ?* ?; V! s$ Q, ~! |+ E. f4 l ( U* e [2 B s6 X% j* ^
Total = 428 h6 O% [1 [! _% w- T/ c$ P+ H- p
上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。* I7 K9 s: ] k& H+ v: w+ a! d
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MATLAB中可用的数据类型 P- t( [% B5 i0 n- [" T6 M
0 I1 `. n0 m, z) n, Y" K' g 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。
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下表显示了在 MATLAB 中最常用的数据类型:
, e+ Y: \- K" |6 b6 A2 x) K/ v
7 A9 C) J! J* E2 P 数据类型 描述+ b0 G0 y8 W9 r7 N0 X4 a
int8 8-bit signed integer
( j1 `, \, D% p3 [/ N( s uint8 8-bit unsigned integer/ C& _$ C# O L0 U
int16 16-bit signed integer* N L, C; f( N$ A7 F; K- c/ n
uint16 16-bit unsigned integer
' ?; a/ R! R! ?, c3 R7 b int32 32-bit signed integer
, i5 W' u* |0 ~$ F# T8 N- h uint32 32-bit unsigned integer
9 _& a, x( _+ ^9 I% D6 U- s9 N int64 64-bit signed integer
8 w) N0 |! r5 c; r3 R uint64 64-bit unsigned integer6 V- V, i2 y2 n; x; d- z
single single precision numerical data$ O" l) c3 {; |7 z! p1 A9 n- x
double double precision numerical data
) u# w7 B8 |* k. w# M/ o logical logical values of 1 or 0, represent true and false respectively, x6 P& y! ^$ b5 s7 \; h
char character data (strings are stored as vector of characters)$ L9 O0 H# f1 @% Q, I: L! l# G/ F Y
cell array array of indexed cells, each capable of storing an array of a different dimension and data type! ^0 c8 s) P7 T8 e; X8 f- W
structure C-like structures, each structure having named fields capable of storing an array of a different dimension and data type0 P7 p. f* v6 b% Q
function handle yiibaier to a function
8 r6 P( s& @) D, m1 \ user classes objects constructed from a user-defined class ^5 D e- Y: j7 M1 W X) Z
java classes objects constructed from a Java class
; l$ J6 k: u( U* G/ V: i 例子5 a; E! S2 t0 g8 ~/ r4 w5 C
9 u- @$ e- p8 j+ h! z& ]. a 创建一个脚本文件,用下面的代码:
! E5 F2 i/ V, d1 l( W a2 I5 A + ?1 s1 ~. T7 N% V2 g0 K( a
str = 'Hello World!'
7 F7 ]- i2 d* \+ a* \! N/ S n = 2345
0 J2 |( {0 i' p) Z$ _: {, ^ d = double(n)
3 n7 B6 b8 Y; x% c4 u4 ^9 r un = uint32(789.50)! h3 @, ~, V6 E* u5 [! l! O6 B
rn = 5678.92347
# H- S2 w0 I5 j3 y% a. _9 U c = int32(rn)
8 N s: W" W: f& { u' T 上面的代码编译和执行时,它会产生以下结果:9 T5 C1 r. w- @& h8 ^
" `' g$ {. _4 E6 q5 X, i str =
5 E* P \- c4 \0 `: m! c/ x* q Hello World!: g; q5 C/ E! @2 t4 D. c
n =% I' ~% T% \! c' }5 U
2345
3 t) b# y3 m+ J& V& u d =
6 F6 X3 b( V# k7 [" H# |, T 23456 k" q/ T7 O @2 G5 T9 G
un =
+ _: w9 {2 W, {, h! t/ ]% u 7909 a: B3 d" O# T% M
rn =
7 K+ t( f) i( D" F: _4 ?. f 5.6789e+03' E; F: d0 M5 G% u4 R+ V0 D
c =; E- `5 E" Y, k1 R8 t
5679+ q# ]0 N1 C+ x
数据类型转换
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6 |! W8 o6 L( |! i! t! H' h 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:
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函数 目的/作用0 I% a+ K" K2 P1 d0 X! h5 q2 w" s8 Z
char Convert to character array (string)
6 s4 a* U) I5 M T int2str Convert integer data to string9 z9 B6 i) d" |0 r5 u
mat2str Convert matrix to string3 @; v4 G% ?0 [7 B* @ T% h+ C
num2str Convert number to string$ X' i: U% h, S( _ o1 Q
str2double Convert string to double-precision value9 G; I/ }: b& Q2 q6 ^, h# c b
str2num Convert string to number/ o+ w. e. q+ j1 v
native2unicode Convert numeric bytes to Unicode characters
2 d# L5 k1 T* L9 b unicode2native Convert Unicode characters to numeric bytes3 i4 h2 v( @4 |. p# r
base2dec Convert base N number string to decimal number
7 ]- U& H, V4 z bin2dec Convert binary number string to decimal number, |) S8 j8 V4 S$ Y l5 i' ?2 Q
dec2base Convert decimal to base N number in string( K! K; |( c- ]6 o! g
dec2bin Convert decimal to binary number in string! `' U/ T) e T7 n j
dec2hex Convert decimal to hexadecimal number in string8 ?5 Z, b6 E7 D
hex2dec Convert hexadecimal number string to decimal number
' K3 b( F1 @; d9 ?7 I hex2num Convert hexadecimal number string to double-precision number
7 J/ R7 G( H, g/ F num2hex Convert singles and doubles to IEEE hexadecimal strings
; p# A7 k: `- ` cell2mat Convert cell array to numeric array
% _& x' S" w8 r# \) W cell2struct Convert cell array to structure array
, m0 t5 ~, G. s9 E cellstr Create cell array of strings from character array
* A. f0 U3 g/ U mat2cell Convert array to cell array with potentially different sized cells
) n/ K, c: }1 J: V num2cell Convert array to cell array with consistently sized cells7 P. M f' ~; R
struct2cell Convert structure to cell array
5 A8 b/ Z6 `' f4 E6 v1 r* K 测定的数据类型
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- z4 c' `$ A9 J( j" U: ^ MATLAB 提供各种函数标识数据类型的变量。
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下表提供了确定一个变量的数据类型的函数:/ `* K) `( Q8 D' ]; ?( D3 [
# f7 T9 C4 K& Q( Y; _ 函数 目的/作用
z0 W# c7 s( V5 b! t) E+ } is Detect state
' }1 V5 K: p1 d: F isa Determine if input is object of specified class) ^, i' r! Q6 N* Z; [& l, _- E0 u
iscell Determine whether input is cell array
* T" H) v$ ?% Q* T# \ iscellstr Determine whether input is cell array of strings
7 Q7 _- o E0 a' M4 ~- t ischar Determine whether item is character array
( G- o' W T: [8 s isfield Determine whether input is structure array field- {! L+ I, h9 ]% f) _, L% }
isfloat Determine if input is floating-yiibai array
! G/ ?1 g* C& i4 J ishghandle True for Handle Graphics object handles' c0 }, @3 G8 a3 k% d" m8 a
isinteger Determine if input is integer array# f; `, u. Z8 g, n+ K. A
isjava Determine if input is Java object y0 F# X6 \! A& @3 `( K
islogical Determine if input is logical array$ u* S0 I4 \9 u V- a
isnumeric Determine if input is numeric array
O2 h8 T! ?) l/ n isobject Determine if input is MATLAB object
- R3 m9 f; _ c1 Z9 y' t8 p isreal Check if input is real array
% ?. O( c6 R2 a- N Q isscalar Determine whether input is scalar" F3 E$ Y+ j) E7 j1 x8 m! W3 _
isstr Determine whether input is character array4 j. M. G2 _+ k/ p. r
isstruct Determine whether input is structure array P( S" T' q. m0 \/ M5 d
isvector Determine whether input is vector
, s7 W z* g; O class Determine class of object
- `& J2 f+ M# z) X% ~ validateattributes Check validity of array
8 c8 B% _7 j4 c/ i) f+ X whos List variables in workspace, with sizes and types" |' _( T9 m( C, p( ]( R- e2 B; h
例子- E' s4 Y _- b8 F. b2 T( i
1 i% J6 W \- L* G' P: X; A! {+ | 创建一个脚本文件,用下面的代码:5 w# A0 r" j" @4 {) [. \( Z
" E. e. P0 B. p3 S3 q4 U
x = 3
2 V* k6 g4 t2 r9 M1 @. l isinteger(x)1 O4 A% _% x. e; I3 w
isfloat(x)
( f# j6 L& v4 U4 W isvector(x)$ b& G' b; [# }# G
isscalar(x)7 Q; e. O$ [6 m
isnumeric(x)$ X& E% l0 M# q+ M5 q7 N2 m
1 x1 K- t1 b- S' p6 b5 ~; \ x = 23.54, |/ H" Z1 w; B8 e4 n; y# L
isinteger(x)9 H- V8 w Q* L6 e
isfloat(x)
9 x) D- c' P) ~( q isvector(x). s9 u s: q; v4 ?! x
isscalar(x)/ x: k4 @. ~4 o, A/ j' w
isnumeric(x)* V- T7 I* d! H) @0 ^
- ~0 Y9 i" ]0 U( ]: i4 T. k x = [1 2 3]" N; y* F7 u7 N
isinteger(x)! M2 G& e; k( S' S5 y- T% {* s
isfloat(x); }& w# v. V" y T
isvector(x)
0 D6 x# @! j, {7 V# O isscalar(x)* l& ?8 u6 @; s4 t8 Q
8 ^$ P1 g% E: H/ V( `) r! A x = 'Hello'1 {" ~7 D2 A; ?( q2 _$ H) Y
isinteger(x)6 E$ o6 L- Z& b
isfloat(x)6 q% ^0 Z$ D0 k/ x9 i8 d7 ]
isvector(x)
1 a# [. @0 C: U" k isscalar(x)
1 i6 \5 [; m, g7 x1 o3 t isnumeric(x)
# \! K3 }( g9 X' p8 m& f 当运行该文件,它会产生以下结果:- \: ~: Z2 x5 S3 `$ k y+ Q
- G( U5 Q/ J8 s9 O+ ~ x =. }: W- Y0 P7 l; U5 [
30 |" i* P& U1 g) X! X: ?$ l
ans =. R( k* N2 B. F- m0 b5 E7 ?
02 N- a+ |7 H& @ Y! |4 y
ans =( K6 e' @3 H/ b' Q4 f ~
1
2 r( o _; j- k C ans =
( V/ J/ O$ F/ b( w 1) k2 c# f7 R- T2 V0 a7 s
ans =
5 m( N5 q' P! D! t/ x: `* P 1- Y) {: j) R2 b* K- A6 k
ans =" k6 L3 L. e6 X4 L
1
1 C" t) y; B. W7 J7 L( G+ E x =
2 z) c9 z+ w. d6 w% m 23.5400
/ n C9 X5 M4 e ans =
1 _, I r) l$ n" W 0
3 s4 s# `! ]5 H4 l- X ans =& m# M$ A5 f0 d" r. g5 P
1: B2 x! F2 ^. P+ O# B( M$ s
ans =
5 @, n) x `: a9 G. Q, O+ U% C' N9 V 1
& b) j1 _: F/ E/ q1 A2 j' ? ans =4 v+ o) H# _: `2 y9 T6 U
1+ M: v( e' ~6 s7 }
ans =+ q, ` i, R4 t5 m- B8 N( E2 n
12 @$ Z, Y+ m2 ~2 w. w
x =7 g( M z5 q' Y
1 2 3
4 P4 x/ B* n* S& ]) @: e ans =! v/ T, x/ c4 ?& _
0 C) f, G/ M8 t6 ] k
ans =. Y/ j- @6 K) J0 h7 h- p
1! h: F; {9 n m
ans =- y9 ], N2 k) x5 `! [) y* p$ J
1
( s, C+ k3 t, r" o/ i5 u ans =
! q8 G6 m' f, l+ B; o4 F x( o& H { 0
9 ?# |0 z% U$ e3 g! S' t9 e x =
0 ~" v( H& I5 f; L( J: K( n g Hello) r4 `$ f; W& G- c
ans =
1 }" A y6 w0 |! l W) l9 m 05 T) c+ {3 c( V/ m
ans =* h! H9 e! O* T X, i* h# Q
0: u7 p9 h) ?; V+ m9 g
ans =
: Z a' s0 z* K" G2 { 1
3 |; V; J: H. H$ B/ _7 J ans =
% G- i' z! \8 ^& R% k1 T 0
8 N5 M" S& W0 x) O ans =# V5 a3 i5 h b/ N, m
0
/ c' J) a; \& o- L! v$ J 7 T* V* e: \9 J1 }9 E8 Z1 t; I# H8 T
————————————————5 _" @3 }8 f }: I V# A
版权声明:本文为CSDN博主「Phil__ming」的原创文章。. G0 y2 E5 X1 U: A. y
原文链接:https://blog.csdn.net/Poseidon__ming/article/details/75092575
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