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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。
) r6 _8 Z: h- A k5 _; y5 }8 A) k. t6 v* e' y0 M7 u9 ~
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。- U( R+ ` r& R( W" R" F* H7 }, }
8 W9 G7 [8 W0 W, a$ G0 Y, w5 ^例如,
: ]. t3 H" Q% Q, Y& y# o1 J* `3 c4 N! D
Total = 42
& d$ k5 O+ y; g6 K2 d. w; A上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。
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' s h& q( X$ cMATLAB中可用的数据类型
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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。2 l b! x+ ~+ m8 u$ q2 K
7 X3 ]( K3 ~+ U: j下表显示了在 MATLAB 中最常用的数据类型:# E( v6 l. X7 d Z6 j
' w: S, `, a4 W( _+ Q; E数据类型 描述! _* ^! @( c+ C4 | T& N( `
int8 8-bit signed integer
% r$ e% M b* {uint8 8-bit unsigned integer: Q. r8 W' \" T, _0 p c2 r
int16 16-bit signed integer
# u& g1 q) i7 Tuint16 16-bit unsigned integer! b. c# a' \; ~6 d7 r
int32 32-bit signed integer. Z, t, n! l% o. r9 [; [
uint32 32-bit unsigned integer
2 P& {5 B: s) p5 T2 `. X0 q' \% N* uint64 64-bit signed integer# P+ w8 `: z" c* ?5 k9 \
uint64 64-bit unsigned integer. p" v: Q, N9 H" D
single single precision numerical data" |; K2 [4 _7 l
double double precision numerical data& R+ U3 W. {8 C) c9 V
logical logical values of 1 or 0, represent true and false respectively3 N, K8 {! K5 G9 L& c" E$ f
char character data (strings are stored as vector of characters)& _$ B* [/ a3 F0 j B
cell array array of indexed cells, each capable of storing an array of a different dimension and data type" `7 @' W) L- R8 ~: _8 m. g
structure C-like structures, each structure having named fields capable of storing an array of a different dimension and data type
8 }8 K0 H' O/ }- T8 ^function handle yiibaier to a function. H8 z( b' \1 K) l( \/ Q6 \ O
user classes objects constructed from a user-defined class1 ^5 J- {; E5 s1 I e) E
java classes objects constructed from a Java class
! j! i' S. J: J4 Z E7 w例子# \$ G! L1 s. z2 K5 F$ \0 E
9 p, x+ A9 F& x9 d* H
创建一个脚本文件,用下面的代码:- {7 M4 m) D( ^* ~2 ]& R, n% p
* T2 A) v0 Z6 X$ W
str = 'Hello World!'5 Z+ n# ~& r7 |: ~3 r1 }, G
n = 2345
* b9 B- }; o8 y ~8 ]d = double(n)/ [# b3 K9 H$ f2 @, w; Y% Y; ]
un = uint32(789.50)
2 n6 L8 u- J, `! ], j# F* Krn = 5678.92347$ a& D' ?. H6 O% y P
c = int32(rn)
; U$ u( K) S) r% w! G: A6 K上面的代码编译和执行时,它会产生以下结果:
: Y9 m7 k# D2 \/ X* _: y9 ^: S% c. s
str =
9 R/ l4 X: B& ?' k2 q7 l8 I) j6 k* j- WHello World!5 d- h$ ?9 d* D! G
n =- _+ d) g2 X, H! X
2345
1 V4 N* ~! d ~- N, Sd =& Z0 H8 i; d0 t2 i0 \
2345, P# ^. v; c6 t8 F$ Z. \
un =( S% b9 W, l) o# w6 u, _& Q8 i6 Y, Z
790
. V5 h4 ]9 {' V5 ]rn =
+ T: D; G* V& [! ~6 Q 5.6789e+03
- y+ B+ M6 ~0 z$ Kc =
5 P3 v% g# q+ i) {" M' U3 U 5679
. V, [3 d+ N% V s* Q; R: e R# ]数据类型转换
3 w4 G( F+ V3 ]" t' J4 G. [' p
# l; z1 `/ ]1 DMATLAB 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 G( f7 N ]9 P; e
" i: F; C5 ~% Y7 z+ U. A, I
函数 目的/作用
5 e3 x. u& x: K. O$ gchar Convert to character array (string)
. @+ y( y7 s% `0 ]% {4 m2 B0 o6 `, p2 Rint2str Convert integer data to string
& P; { Q1 J' ?" Smat2str Convert matrix to string% F8 ~' E/ a: _/ W: J/ s6 _7 ?" Y
num2str Convert number to string
; {6 h( s$ B9 _ O, Hstr2double Convert string to double-precision value
8 v( K% i' @$ N& r% M( rstr2num Convert string to number
# I: |- e. j; p6 x; [4 \* xnative2unicode Convert numeric bytes to Unicode characters
. B6 y/ O- h6 L3 o" Iunicode2native Convert Unicode characters to numeric bytes
9 z1 z+ E5 K9 E$ `# [. mbase2dec Convert base N number string to decimal number
4 b, w8 H. p0 d& C L# ?0 Nbin2dec Convert binary number string to decimal number
; F) s+ r) E3 k. I: X! }4 f* s! Gdec2base Convert decimal to base N number in string
, x: c' a0 N4 c. e: _dec2bin Convert decimal to binary number in string3 d; ]: o7 m+ n2 n* ?9 @7 {0 f
dec2hex Convert decimal to hexadecimal number in string) G' ]3 Y& u, y
hex2dec Convert hexadecimal number string to decimal number/ \6 r2 s- ^* S& o; {- @! ~
hex2num Convert hexadecimal number string to double-precision number
% k! O+ Q: \1 @. {8 nnum2hex Convert singles and doubles to IEEE hexadecimal strings
; J2 R5 {; V4 m& B' A+ ncell2mat Convert cell array to numeric array
b `) c9 \! V/ [3 W% }; _! dcell2struct Convert cell array to structure array
7 c* z1 ]# i, D K8 Z) K5 ]# u. Tcellstr Create cell array of strings from character array2 T+ R7 v" z9 ~( n* T( u
mat2cell Convert array to cell array with potentially different sized cells
) e- q9 T# {( X$ n3 Bnum2cell Convert array to cell array with consistently sized cells
9 w8 p1 Y, _$ ?8 } N$ U0 F7 estruct2cell Convert structure to cell array
. k' |3 H* O/ `+ i测定的数据类型3 G2 C( D$ e. e ?% X
1 Y5 Y# Q# h h. P$ g: ]0 G
MATLAB 提供各种函数标识数据类型的变量。! s* J: m, @* @& e: r9 X
6 V; _" e' Q( `* M) w0 {1 b
下表提供了确定一个变量的数据类型的函数:
5 E( C' ^" M a, ]/ m% o% R$ c! _- V5 B6 [/ I2 f& A
函数 目的/作用
/ B0 [1 ^ a% w% Y! c: x: ~9 q1 qis Detect state9 z. c2 M4 l9 k8 L% g7 N" ^+ E9 D
isa Determine if input is object of specified class" T$ w+ t# w$ g
iscell Determine whether input is cell array
, M( W e9 U0 L, j& E" Q! Oiscellstr Determine whether input is cell array of strings
" H5 V5 K6 u' s$ Fischar Determine whether item is character array
5 U5 t4 ]& u3 F0 ^2 r! ?isfield Determine whether input is structure array field, H, T) V+ j C8 o ~1 ?5 [5 `
isfloat Determine if input is floating-yiibai array
: Z7 E/ q4 F" R: ]+ y$ Sishghandle True for Handle Graphics object handles5 m, H" F. i' a% G2 F
isinteger Determine if input is integer array3 C( y# B& q. d" p7 z
isjava Determine if input is Java object
: q6 X5 |" ^" r/ @$ N# t' {islogical Determine if input is logical array5 a# i, g2 }4 m( K' y
isnumeric Determine if input is numeric array) D" B( W( G* g$ t7 }$ i
isobject Determine if input is MATLAB object
4 Z& {# M* Q. R" H" Xisreal Check if input is real array3 I' Q2 f6 A; ?5 f7 w9 D K# R
isscalar Determine whether input is scalar, z0 a6 f" T! ?8 }' ?
isstr Determine whether input is character array
$ w: f2 l8 r# q- o. Visstruct Determine whether input is structure array
6 y7 M) W- S& A0 i bisvector Determine whether input is vector
9 z) Y7 {$ {3 u7 h! Cclass Determine class of object) e% M$ x5 ]# Y" o9 C
validateattributes Check validity of array
' @4 X' h3 K) C2 p( y! h& zwhos List variables in workspace, with sizes and types) o! J! Q+ X4 j3 G8 T; j! @
例子
# _5 U! k$ _( Y1 K4 \& `' s
! Q- e' Z+ y5 B0 ?/ U; U创建一个脚本文件,用下面的代码:3 P1 z) Z6 j4 j! a$ t6 i
2 ]) X% ]$ S( D9 j7 O! V
x = 36 `+ d/ Q& z* L& ]
isinteger(x)
; R6 r9 M3 g, W8 m# E) qisfloat(x)
; Y( Z0 \3 H q) V& }isvector(x). l$ Z, h- }" D( ]" |4 f
isscalar(x)1 Y: ]/ _; I* }) z: p! g3 J2 k* | S. R. Z
isnumeric(x)
H7 [: r8 T9 z
& P' w* w, w: p9 Wx = 23.54
3 r3 ?0 Z# u# s6 z5 b; v7 L2 Xisinteger(x)
/ D! h. u/ \3 T6 ?0 Lisfloat(x)" U% T1 A/ i. m$ Q5 F7 z0 z" \
isvector(x): d/ ?1 W: {5 e# R# M7 a
isscalar(x)
- d! D+ d, U a% Nisnumeric(x)
$ y, e* x4 P0 j& y8 y9 w! Z, N1 ]
* \% k6 ^) {0 G% f3 o3 b; Z3 a: }& Mx = [1 2 3]# c3 B- m3 Q, F9 c4 n! g
isinteger(x)4 L8 `" H7 C! u: i- Z
isfloat(x)
) f2 w1 `' W4 Q/ E4 n$ cisvector(x)
5 Q" l# l- J4 h6 X4 K: f3 Xisscalar(x)
* ~: S: T* M) R' M K7 |% F$ `
; i2 \( K, G5 ?% F4 N" Qx = 'Hello') W o. p- `& z/ `
isinteger(x)7 q1 Z8 R& s, `# k3 |. N9 g
isfloat(x)
- @7 _( n2 I& L8 r, w: n) misvector(x)
7 c# L! B" I# q- A( Kisscalar(x)
6 y: Q/ v6 r8 z; E6 F0 b8 h) Sisnumeric(x)4 }. e: D% I- T9 q% W4 a% X
当运行该文件,它会产生以下结果:1 f' d( D9 v1 v4 p6 g0 n* V
& b( p7 z) Z2 N" F+ O# u6 d
x =! M0 e3 |6 n# n, G
3/ d8 x0 u) p9 W8 y- d
ans =
2 a' K% E9 A; [2 q+ ^5 K- `1 d$ B 0, |( X8 U7 G- v$ B/ S
ans =& [9 Z5 S7 M" a8 x' O9 }
1% U$ E' m% j5 R; Y2 V* H6 ?' F
ans =
* F4 [: E6 I* W" ~$ K- H2 h 18 s7 j7 e$ S0 s. T' |7 f) \5 R
ans =! @! I8 A6 _8 R8 `6 w4 ]
1
* ^/ a6 n6 w, t+ ?ans =3 ~* v$ N4 ]* G! c) a, Y
1
: {" q$ s/ l$ R2 p" cx =+ ?0 P* s2 C3 P
23.5400
$ l+ f8 H: o8 |ans =7 y* `8 Y1 g4 ^' K
0
/ L4 o) A* A0 L: f/ A( Uans =
& c5 b' @2 v/ I/ M2 x" F 16 A& V. J9 p) d& c
ans =
( _4 N9 g8 w0 X9 `! U 1& K" U$ C; T+ x+ `& X
ans =3 B7 l J: _ l1 d$ M4 T
18 Q: I! y5 N8 h# q$ l9 o& O
ans =1 H4 F$ ^, _7 _5 _5 R9 V
1
2 E$ Q7 x. C3 _7 b: z6 W% Ix =- ^9 S h" x2 `2 D; `
1 2 3
, a3 b/ z% O+ g: V+ Nans =$ h3 s7 G' B* v$ W2 B+ [) K
0
+ L5 L4 {5 P+ |" Qans =
% y1 H- f0 g( D: C 1
2 w1 V# y- R( y+ u$ v# ?- ]ans =4 l) ~7 I+ \( T2 X, d
1
) I) y5 Y9 N# s3 G+ Dans =' n% U# B4 [9 S: X& d3 u
0
0 O! I* U7 d0 E Vx =. f; G6 P% J( T% y5 q: E4 @2 k4 s1 x
Hello/ q1 y7 g6 T( Z; g, J$ ~2 p
ans =
( m6 \# j3 ^8 L" a! J0 ^7 J 0
: [' e8 X; k* ?) ~& ]1 s' ?) eans =
5 f4 ]0 v! D" Q 00 U3 _' @9 {$ m2 C
ans =
) C% w" P% U. e6 R 1
- ~* C0 C) H, g% |5 g* z" jans =
/ b$ N, W! x& w' [ e 0
7 ?5 v) q W1 O% W1 _2 Lans =2 v5 h$ b, J/ _! O
0
; f$ ~+ Q/ ^( b4 P* |- I1 O1 V9 A+ x$ g$ v
————————————————
9 z7 ~- Z6 i- ^9 U1 g版权声明:本文为CSDN博主「Phil__ming」的原创文章。
* }# y# y9 `1 Q% M1 p( e原文链接:https://blog.csdn.net/Poseidon__ming/article/details/75092575' S& l& u' ~9 k! y4 d3 x- P0 E1 `) B
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