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TA的每日心情 | 慵懒 2020-7-12 09:52 |
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签到天数: 116 天 [LV.6]常住居民II 管理员
 群组: 2018教师培训(呼和浩 群组: 2017-05-04 量化投资实 群组: 2017“草原杯”夏令营 群组: 2018美赛冲刺培训 群组: 2017 田老师国赛冲刺课 |
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。& I1 a; n* N$ N z# I
! z; k* R+ d9 K, D) o6 i4 {. d
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。
! h6 n. F; R) s* m4 k# x* a# M% [3 d
例如,+ B8 U! o7 k2 `: F. V
8 l; t0 B7 } p( E; f) i
Total = 42" l3 h. U/ C# }: g
上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。3 [& b) u( o$ s# R1 k) C: Y
- ^3 B( {4 N4 F
MATLAB中可用的数据类型, n; k! e- _, T7 y
+ E) ]" q- D6 Q9 uMATLAB 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:
! O1 i8 B: _9 u) j+ |( i7 e3 G5 q1 A- H1 e$ Z1 D! r- y
数据类型 描述
$ ^) f& m) y5 l& f t9 C% A3 ~int8 8-bit signed integer
' _3 ]4 w; O) s8 ?7 _- C, @& p6 muint8 8-bit unsigned integer! u! R0 G% k: B9 G5 L6 ^8 c
int16 16-bit signed integer
- |. `) Z7 L: U8 x4 [- L( Fuint16 16-bit unsigned integer3 w/ i& }6 h! j8 ?3 R
int32 32-bit signed integer8 [1 ~0 } B% \
uint32 32-bit unsigned integer' @3 }0 S2 F+ e1 R& A# r
int64 64-bit signed integer9 [/ X8 q- S) {; k0 c
uint64 64-bit unsigned integer
( f( s7 d8 k0 z$ a2 ^single single precision numerical data, s9 C) h- ^) w) H( x8 _
double double precision numerical data, r) o! i* z2 _3 |! A! ^* ?
logical logical values of 1 or 0, represent true and false respectively
" A8 g' m$ |5 G3 f2 v0 T6 Nchar character data (strings are stored as vector of characters)4 y5 w% G2 x) e" o, _0 N1 x3 T
cell array array of indexed cells, each capable of storing an array of a different dimension and data type- s$ c% r2 c. Z7 g- n7 i
structure C-like structures, each structure having named fields capable of storing an array of a different dimension and data type E7 m& @' b5 k
function handle yiibaier to a function
$ V; M v; k% E g) Y# Wuser classes objects constructed from a user-defined class9 A+ i1 n* C3 o; _" T. W) K
java classes objects constructed from a Java class3 n! e3 r# S9 @/ [9 C4 J' Q
例子) D8 n; s/ S" W+ D, C9 Q. s i
9 s5 w4 q4 T x o# i! Z创建一个脚本文件,用下面的代码:
' R! l- p; c! [. r e2 Z8 w* z2 g( b9 k0 a+ @2 @1 _
str = 'Hello World!'# K1 ~( o' n5 ~0 O! W
n = 2345
9 O# `: y$ ^6 t0 `* j5 ?+ }d = double(n)& O: \& H4 e+ L. _! R" q
un = uint32(789.50)
3 _5 [" L2 s( B- \; Wrn = 5678.92347
) |. S; F- E. H6 oc = int32(rn)* g* \$ t. Q) ~! W2 ?
上面的代码编译和执行时,它会产生以下结果:
! u8 p0 F3 B) a$ A' `# \5 B. ^/ F4 N3 H( b1 z" h
str =
+ l: e6 g0 w" U' X! V( c) mHello World!% P6 T& ] S0 I% }
n =! [% [2 K. K; M' T
2345
' K5 A) F5 l: E6 R/ G+ K! od =
I& C0 a9 m* _: ~; X, I" A# e3 j 2345$ B$ N% v; @. u; Q! I' S, L
un =/ p3 t; f2 g/ \' m# T3 |7 o
790
3 w+ T) l2 R: m6 A0 w" X, Vrn =
) m0 m# ?) G& b4 }0 o% {# B) v9 ~ 5.6789e+03
t: h& M3 k; kc =! C5 r+ Y C% z2 t! q- ? x3 T/ q
5679' U# I- n# W+ h! ~& @# q* F
数据类型转换
, C, e% y6 D1 O" z3 a' e. G! e& ^1 G6 F7 j6 _# }* `4 O1 V
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:
7 O" M- e7 C% O3 V. P; ~& f7 |- f' u4 b; N( \
函数 目的/作用 g$ L, ?1 j) i9 K
char Convert to character array (string)3 K& m9 Q# m* m7 M
int2str Convert integer data to string
: V$ e, p" d; s' Xmat2str Convert matrix to string# Z" B4 {6 A9 M. r3 [4 h4 c
num2str Convert number to string
$ p4 j2 I' ]& S. j$ L: Cstr2double Convert string to double-precision value( v7 \% W) e" R' m' i. l: w
str2num Convert string to number
1 z) w, Z0 b7 A; s8 X5 g+ @8 ?native2unicode Convert numeric bytes to Unicode characters2 w" G! n) D. K! r7 K: ~# z1 P
unicode2native Convert Unicode characters to numeric bytes
; H% s9 f9 N* [8 @2 e9 wbase2dec Convert base N number string to decimal number: ]$ k' r. Y, [& @
bin2dec Convert binary number string to decimal number
' d1 t; w5 J) e( [/ Hdec2base Convert decimal to base N number in string
) Z& j3 N6 u: l2 _0 Tdec2bin Convert decimal to binary number in string
) y# T/ T% D2 u2 ^, z$ vdec2hex Convert decimal to hexadecimal number in string7 K- ]( }+ x: j& T' b t8 \& U/ m
hex2dec Convert hexadecimal number string to decimal number1 y7 q& n" S0 z+ d
hex2num Convert hexadecimal number string to double-precision number
' K, s, X' [+ U2 `: t- E$ _2 Bnum2hex Convert singles and doubles to IEEE hexadecimal strings
, [% T8 c9 U6 e) i' ocell2mat Convert cell array to numeric array" K9 M) \. y% N" r- `
cell2struct Convert cell array to structure array. M, b7 k0 ]+ t( }
cellstr Create cell array of strings from character array& s L& P! K. U# [5 \
mat2cell Convert array to cell array with potentially different sized cells
$ L: ^* f7 d0 J2 I# Hnum2cell Convert array to cell array with consistently sized cells
( ?# z* O1 c, s/ ?struct2cell Convert structure to cell array W% r( J5 U, @: ^
测定的数据类型
& r1 Z9 f; \7 y5 O
$ t6 p3 t( x' |$ q! @3 M3 @1 R0 ?, ^MATLAB 提供各种函数标识数据类型的变量。
$ _4 F: ]. `" ~! p7 O) I$ Z! x" E4 @! W# `/ F
下表提供了确定一个变量的数据类型的函数:. I$ U4 x* i V# T+ {9 B! v6 W; s( o9 F
9 e# v& K7 @' j0 C8 y: |6 H
函数 目的/作用! X( _' `: E- q4 `5 ]
is Detect state
! R4 q w6 ?) v) D4 Cisa Determine if input is object of specified class
: b/ J. l/ ^$ A) ? M9 e+ y a Aiscell Determine whether input is cell array t* x% J/ R9 S" W" K! _' {, C- B
iscellstr Determine whether input is cell array of strings
* B) z( T- w8 B/ f- Xischar Determine whether item is character array" f6 V) z S D
isfield Determine whether input is structure array field' a1 k4 M' K1 L2 X; `
isfloat Determine if input is floating-yiibai array/ A P! m' p9 l" Z, A" J- J
ishghandle True for Handle Graphics object handles
$ A) y+ E' D, J( o! Y- b8 ]( Uisinteger Determine if input is integer array/ h2 Y# a3 ]7 P- U
isjava Determine if input is Java object
' L- w* F1 @4 u: D& F1 |7 vislogical Determine if input is logical array
& Q$ M2 w! z/ |5 Z: [' _; C- fisnumeric Determine if input is numeric array
$ w: h# C, H, x6 k! m. i$ k. K/ eisobject Determine if input is MATLAB object- K/ @; n( A" i2 A7 T1 k5 p( Y5 t. _
isreal Check if input is real array& D. }7 G( z! z; m4 t
isscalar Determine whether input is scalar
; f- e" N% V; s3 A6 Z0 L* R3 p7 misstr Determine whether input is character array
5 s/ l* v# u4 p. x+ q$ ~8 Y H. Cisstruct Determine whether input is structure array6 c7 Q8 ?0 Y1 F! t. r7 N0 W* Y
isvector Determine whether input is vector4 a& q. h7 |% m% ~9 |3 c
class Determine class of object( R# @& Q: g0 K0 f/ t8 X* u8 P9 u
validateattributes Check validity of array+ W0 U& W B" `$ S9 F* ?
whos List variables in workspace, with sizes and types( W1 P2 [3 w( d: U8 x, [
例子* X. S* H. j# Z# t# a$ g/ F6 |+ d
6 d* U* d, x k2 K: n; N# E* c) ?
创建一个脚本文件,用下面的代码:
$ |+ ? D7 E: W* o' z9 ?4 C. A2 [' q) I% n3 Y
x = 3 }( P2 V+ H! {$ j2 ?
isinteger(x)
1 y8 } I& ^5 O! N4 R visfloat(x)
! H7 F9 q4 L+ ^5 X4 s- Z8 Zisvector(x); J+ Q q: K' I* H2 [' y
isscalar(x)7 j: h, S* P0 @2 b2 F3 w, |) Y
isnumeric(x)* s5 R. h2 w- P2 }$ G4 N( M4 ? p
$ o7 d/ w, o( j9 _9 c. Nx = 23.54
% o, a: R. @+ Lisinteger(x)
6 w, g) q) j; I2 f( L O8 ]isfloat(x)
5 n$ [/ O& M# i$ J! gisvector(x)2 W* I6 P; k( g
isscalar(x)( d3 m& s" j2 p/ g4 s
isnumeric(x)
# d, x4 e* N8 e2 f: g4 V
' l8 T3 c3 L0 s: F! a) L: |x = [1 2 3]3 ~: g/ y. g% Y5 p/ k5 y
isinteger(x)
* H6 B4 r0 d) v3 j. _( ~7 gisfloat(x)
1 h6 O/ N9 Q4 }isvector(x)7 h7 I& k& f- q3 Q7 K. `3 z
isscalar(x)7 F% I2 Y" w6 M+ U
$ e& N, v& u8 k, xx = 'Hello', a9 K' X K! w- ]. {: B2 `. w
isinteger(x)
8 M) q4 R) {9 Qisfloat(x)9 Q6 _( q1 W# }% ^: i' |
isvector(x). N3 N3 v9 ^" E; q
isscalar(x)) A) m! Y* g7 Y3 _0 d1 R; ]
isnumeric(x)
' s/ B# h! M9 f; R) L s当运行该文件,它会产生以下结果:
( K: g$ d2 V$ b0 O
3 w9 F) W2 W, v5 ]! q. L/ ox =2 D! H, Q$ I: F4 u4 m
3, ~; o9 n3 d; I
ans =
- j6 I7 `9 d- v ~4 \1 B" c- ] 0
8 D. }% P8 x& F! a: [2 {ans =
0 y% o4 }. }$ S$ V7 x+ D 1
1 ^; j; P. h( i& p' p1 B. ~4 lans =7 C; W f# ?$ }
13 X; o9 g" Q' p3 y y
ans =- e7 ?3 H9 g8 x
1$ b, l* E/ b. z/ D' k
ans =4 C, l' v. A6 h' I2 H! a
1" z. x: [6 U4 s& u+ g/ P
x =% n. |. r& E+ X
23.54002 ~1 I4 L- c: `( u" p; H, d
ans =8 O' i# O8 M3 d+ c7 p
0
' ?3 s% z+ @3 Jans =
; x5 n8 l3 N, t; }3 K 1& [5 D6 k; r0 ^3 }$ l& M* W
ans =4 q6 k) M4 o6 T0 m: u' s* g
1
* b$ h) Q' F7 C, j8 O; z+ `ans =; X* a1 Z# b1 {6 H% J! I
1
" U" D" `$ C& b7 R' W: N yans =
" g7 w% B1 N4 N 1 t9 R: P$ u, b1 p' [' }
x =. c% b+ }! D' U$ X0 y8 H0 ]4 o/ s
1 2 3
7 J9 E6 L' s7 v8 X/ m Q* Dans =
) X# a/ g$ H; y% } 0
4 V1 V: v/ x7 ^9 l; mans =% g* ^" y' p+ L! T: B- O8 p$ h" D( L
1! K1 }: M! e( I E6 _
ans =
1 c+ a! N( g2 h 10 h. R$ {) A5 u
ans =) o9 @: H7 F$ \4 V# ?2 G
0
$ A& |' O( ]0 Px =
5 A X6 @4 |- n; d) tHello
0 u. F# X3 q- h0 H0 f+ tans =, w4 U, d( E! D/ R( q. `
0
/ \4 ^+ C8 A' U3 g* a: Qans =* _( n; ]# `; X/ @& O
0
4 M, O g- T8 ?/ z$ j- E6 lans =% c$ d+ U$ ^) ^! K9 V
10 H1 O2 N4 i- R& R- _7 L* [ b# S
ans =
8 t# K8 ^8 J+ b4 J! y- H$ [/ B 0: m( b" J7 @+ R% J, D
ans =
, q, L6 ^1 R# N) e5 e 0
/ D% A; s ?" f5 M# V0 r/ |! J6 K: |4 z7 q
————————————————
/ u x! D8 D9 T6 i g1 E版权声明:本文为CSDN博主「Phil__ming」的原创文章。
* ~( i1 Y2 C( a+ P原文链接:https://blog.csdn.net/Poseidon__ming/article/details/75092575
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