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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。6 |' |! z) O8 g/ ]. p8 D' E
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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。 z6 i9 }* z. x( D2 D& _
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例如,8 `1 D& E2 T" v5 q6 G: @
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Total = 42: q, u0 J* X y: I
上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。. Z! p n# {) U
1 R* u# x2 j! m, IMATLAB中可用的数据类型 D; m3 J6 J2 o/ p
& O+ X7 y; `- W) j$ {, a8 c6 ~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。
) Z" O! a( c5 O R" z5 S3 O9 r+ n8 A
% ^& r3 o2 U% i下表显示了在 MATLAB 中最常用的数据类型:
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数据类型 描述* N9 K3 d& l! L) ]: c2 f1 X
int8 8-bit signed integer
2 u: z4 r! p1 @9 d% g( Buint8 8-bit unsigned integer, j$ O5 _# Z! g v4 F
int16 16-bit signed integer
: ^5 ]" x+ V7 B6 C! {1 p8 Ouint16 16-bit unsigned integer
! E0 S, g8 G+ H$ }int32 32-bit signed integer, @2 z) L0 r0 A# B% `4 ` ?
uint32 32-bit unsigned integer
+ ^* O! M. C' ` z( |: `3 G* x, Uint64 64-bit signed integer+ n5 R2 t, o1 K( ~ Q, n
uint64 64-bit unsigned integer1 w- q' o7 o9 V1 n7 {
single single precision numerical data4 v7 e( L8 S+ B4 O: L9 i1 z
double double precision numerical data
% a1 Z7 M1 m; d! w* xlogical logical values of 1 or 0, represent true and false respectively
+ s4 L1 r+ K! x" Tchar character data (strings are stored as vector of characters)
) J2 B- |1 ^! l7 R& Ocell array array of indexed cells, each capable of storing an array of a different dimension and data type
" X3 d5 D8 J I; i8 ?+ O- ^structure C-like structures, each structure having named fields capable of storing an array of a different dimension and data type, t4 ?/ L2 o' Z9 c, ]0 P5 t
function handle yiibaier to a function9 _3 N: z; [. k; L) u8 Y
user classes objects constructed from a user-defined class
( t5 s% g: `, M7 d* djava classes objects constructed from a Java class
8 q: i7 r5 {' J* S例子$ ?2 ^6 L6 a r% R
, f! U+ f2 M+ k
创建一个脚本文件,用下面的代码:! p7 @! `. u# x
: ?$ o8 E0 r$ w/ ], a d str = 'Hello World!'
' o- \ J6 c) v: o. F& Z+ d( r! E+ kn = 2345
9 p) ~# |8 v1 z7 E) E" L( ^) J3 ]" cd = double(n)
% _/ _9 [ g2 n- gun = uint32(789.50)
# x/ J9 T f: A8 m. P4 Zrn = 5678.92347
1 S. W# P1 R$ g- [& c( I- [* |c = int32(rn)
, Q) q" ~3 }0 {& `# V上面的代码编译和执行时,它会产生以下结果:+ E1 ]2 u( Y0 a! U2 @
. d2 w5 t, E: {$ n/ h7 ~7 q/ a
str =
2 V3 M4 e- B, P3 _; `5 |5 CHello World!: y+ C1 K% g W
n =
$ _ i% U# l1 j1 c3 T( R 23456 q0 s$ r# Q& T
d =, H8 E' L& u% M/ S
23452 ~; J }( ~5 f6 w( N; _& C
un =
' S5 j' o1 z8 o% x" O 790! D4 l3 M. M2 a8 C7 k) U5 F
rn =+ z& O+ J6 Z( o5 b; n# f; J& h2 O
5.6789e+03
1 a' s; u6 }' X6 g& v8 Ac =
A+ s* B) ^! X* V& g! {" \0 d 56796 W: S- G* s4 L1 N' D
数据类型转换
* B0 O- t' |; l2 k
4 I0 I8 E) M5 @" L% jMATLAB 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:
% K# `4 o: V: r( m$ v( m9 {+ o6 X7 z* J
9 H9 ^5 D ?( [函数 目的/作用7 Y$ x, o1 q0 | H, U/ ~2 w
char Convert to character array (string)) N* Q$ |) {7 V2 t. V
int2str Convert integer data to string
6 I/ \5 b6 t, n! g2 f9 m! S& nmat2str Convert matrix to string: ]6 y$ u- x+ g- [8 Q* n( w
num2str Convert number to string
G: g# {. U/ p3 Ostr2double Convert string to double-precision value
* V- G# F% k$ \9 r& zstr2num Convert string to number
0 O5 {4 Q' G5 E) |. l; c7 I1 K( enative2unicode Convert numeric bytes to Unicode characters' ?1 L1 X3 L" ~
unicode2native Convert Unicode characters to numeric bytes* x1 T, b+ q }8 S7 d: D
base2dec Convert base N number string to decimal number
7 |* [* ^3 z# Pbin2dec Convert binary number string to decimal number
4 J1 \7 y5 J2 d8 Q5 d$ ]) Zdec2base Convert decimal to base N number in string
# a1 R2 r. n3 @9 m9 Bdec2bin Convert decimal to binary number in string
) ?1 c6 @1 o Y! P4 kdec2hex Convert decimal to hexadecimal number in string* g( j8 b! q* V7 c& I5 `
hex2dec Convert hexadecimal number string to decimal number
* i% `4 J& G% `5 b9 i5 f& @; Chex2num Convert hexadecimal number string to double-precision number
) r9 E, U/ C5 u' ~* |5 d0 xnum2hex Convert singles and doubles to IEEE hexadecimal strings
7 Q+ ]+ i2 V- t0 j( C. B6 ccell2mat Convert cell array to numeric array( H2 r7 U: J1 k! r4 {" x
cell2struct Convert cell array to structure array
/ s0 b; R6 k- j) Dcellstr Create cell array of strings from character array- g1 u6 w* g9 N9 ?2 O$ Y
mat2cell Convert array to cell array with potentially different sized cells
7 n8 j% M+ N6 y/ knum2cell Convert array to cell array with consistently sized cells
( W! e3 V- u& H8 F9 A' ?' I3 \3 y' Gstruct2cell Convert structure to cell array
1 D6 g) S! [* G测定的数据类型 E/ ]& A8 n6 l. Y/ T( n. V. r
* C; Z8 O: f9 A. A8 MMATLAB 提供各种函数标识数据类型的变量。 g% v: Y+ e* i* ~, F
9 G4 ]' C1 \7 @9 ?: u m
下表提供了确定一个变量的数据类型的函数:' q" k) ^) u% s* C6 O' t; V
+ l4 A! T% i- r8 c- A& d' ]9 ~8 Z函数 目的/作用
+ J" U9 X: f) z& V: f7 Wis Detect state) W1 i/ y6 N/ S1 d6 k5 E) ]- D
isa Determine if input is object of specified class$ e5 e" J+ B2 J, L+ Y* l: m1 F9 |" a
iscell Determine whether input is cell array& `% ]$ ?- h& H7 j9 ^
iscellstr Determine whether input is cell array of strings2 ?, E- H7 b) R. H
ischar Determine whether item is character array
; v' f/ L5 J; w9 Kisfield Determine whether input is structure array field
" I# o* ~* C& E* tisfloat Determine if input is floating-yiibai array* z& m6 S, w0 o; g7 q: i7 ~
ishghandle True for Handle Graphics object handles+ a0 b8 ?2 m6 B. h9 ]" I
isinteger Determine if input is integer array
6 Q2 E7 T; b& z% z3 bisjava Determine if input is Java object
5 R' g% T' t. x7 Mislogical Determine if input is logical array
% N! R6 `+ v1 [$ Risnumeric Determine if input is numeric array* |0 Y; \0 x$ W- K3 x; }
isobject Determine if input is MATLAB object) }& X! P F9 B7 ^8 P
isreal Check if input is real array y: [4 f2 P8 {( s& x. s
isscalar Determine whether input is scalar4 o9 ~$ U' t8 {2 q& E4 B, f
isstr Determine whether input is character array
3 M! M9 E4 {6 H' I& |isstruct Determine whether input is structure array, C# }# v9 l5 I" H0 T; ?* r
isvector Determine whether input is vector' D+ r9 |% g# c4 U) w, N
class Determine class of object
( D: e+ m: C3 y4 l2 h' d5 Kvalidateattributes Check validity of array
' i) `8 X; [" E, ~* Gwhos List variables in workspace, with sizes and types
. `' p6 A' _0 e$ k: }例子
/ I! p' q/ q2 r$ B
! j$ Q: n- }7 n0 u. Y, e6 N3 ~+ w1 h创建一个脚本文件,用下面的代码:, U( x8 W- _1 M" W& ?1 i# j9 z
, L5 N: u4 ~0 o2 cx = 3
* r" b; D# E4 O$ M( ?isinteger(x)
# j6 ~ M) `5 I3 C* J- kisfloat(x)
# a+ m; a4 o2 b: I# B( oisvector(x)
5 p, P3 J, j3 u" D/ R1 r. Nisscalar(x)* w+ [# [2 K: G' ~# L' t0 t6 L
isnumeric(x)& A( j7 z0 |5 H" m0 L) q3 ^
o! c$ \/ l+ a- m, f2 fx = 23.54
D) h9 q5 V( f( e; b& l, Tisinteger(x)
) ^6 W; K5 x* }9 z" V4 wisfloat(x). |5 c( q. y' b( A- [! e# j' w
isvector(x)( Q* E) n4 i& ?/ v7 }# N
isscalar(x)7 B1 Q$ I( |0 u( M$ r6 R7 y1 [4 ]
isnumeric(x)
% A: W5 }; V+ M+ p/ V
* E& H( I$ J% n A7 D$ d, w: M, px = [1 2 3]# f- a3 d7 y( U% B0 g3 T2 N# T1 `
isinteger(x): {, a+ `7 ]+ p9 |0 W' G+ ^
isfloat(x)
5 w' p+ ?9 K% l4 Yisvector(x)
) \* r1 N2 ^! Q6 B. Z) Xisscalar(x). e* P8 i, s' M8 a
5 D+ n- O1 O' ~, `& k8 M9 m
x = 'Hello'
* P+ z5 p. r0 k& b! Gisinteger(x)- m! U0 f4 y" |$ J
isfloat(x)
" e( ]4 s7 P% u0 Iisvector(x)
$ L+ H2 U+ \, ~8 @& d8 o) [ Visscalar(x)
9 R" X% L' B- P2 A7 ^& |. yisnumeric(x)
7 ?: w+ I% w' ]% o, _当运行该文件,它会产生以下结果:
# n8 p. F( e5 n: y1 |
8 k# O G) s, W C+ j6 jx =# ~! J, X" a. H( ]- Z
3
" {, ~8 H7 m+ I# n2 h- l5 Wans =* {: f+ q, N- S, T+ x+ K
0( H8 p0 }( r3 w9 |5 P: e
ans =
7 M/ S% e* n. p" {+ v 1' C% L* V: Q7 K7 Q2 }0 g) |
ans =4 C, [( q% ]1 J+ q- M# W
1* J: [; L {; N/ X7 l [2 e+ z
ans =1 C9 I+ \) T; D* \
1
- \) Z; V' X5 ~ans =
9 X7 W1 F2 t A$ a; d! E 1
* Z) e- S& t( y: Nx = ?% E1 U; U1 f
23.54008 O/ o6 x( y* G& A C. F8 ?
ans =
) k. J! W0 t3 M Q! H4 g 0$ f; q! V) L$ m" M
ans =
/ s4 O) {9 C4 D/ l' k 1% c: @' w. z0 c
ans =
2 J3 J, y/ w3 U4 Q8 i 1# E9 x0 m# X: N1 ^) c
ans =
, M' i+ Q7 Z* S* { H q& e# q 15 v( B: L1 R# K3 a7 X
ans =, p( w V" T% l( R/ w) E
1 _' F; k1 c' ~0 X$ h
x =' }$ u7 G1 N: r% C( J* @( z) |
1 2 31 `3 O. T, ]- `6 b/ p+ b# I
ans =5 l% z' j6 p5 {# H0 Z+ ?- C
0
8 `: \. [9 H7 e+ @ans =
9 b+ F9 P r8 ~# T! A 1
4 p% e m R- q% d3 u' N9 z7 Zans =
^3 \6 i3 M' @4 K 16 a0 W2 d5 m2 q W9 h5 ] ~
ans =; j" Z5 }+ Z7 j4 U+ h& A
0! t4 P8 m4 d5 Y4 q& b
x =- `% V$ V% q% E# c
Hello
+ Q% X% A* r, V% B+ cans =
1 l4 C# n, T5 B+ ?* W! A; t! D1 x( m 09 d8 b# F' h- P8 V/ m) u: u
ans =) a5 f9 x/ p' A
0
$ y0 R! P- n# f. N2 ~" ~ans =
* f' Z! g3 r. u+ b$ U! d 17 [4 ?; v- m. I
ans =- x* h) e8 g: [( y0 d
0
. I8 K8 B4 A) ]0 Tans =: ~# s- P! m4 e8 q7 P. B7 \ k
0
9 Q- U) n I( [, J; A! f7 e& j" c
- {7 w0 z) o; {- Y————————————————; _: L3 f0 H$ U+ a6 w* ~
版权声明:本文为CSDN博主「Phil__ming」的原创文章。' n; F2 o3 _* h/ }! Z
原文链接:https://blog.csdn.net/Poseidon__ming/article/details/75092575
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