- 在线时间
- 661 小时
- 最后登录
- 2023-8-1
- 注册时间
- 2017-5-2
- 听众数
- 32
- 收听数
- 1
- 能力
- 10 分
- 体力
- 55543 点
- 威望
- 51 点
- 阅读权限
- 255
- 积分
- 17614
- 相册
- 0
- 日志
- 0
- 记录
- 0
- 帖子
- 447
- 主题
- 326
- 精华
- 1
- 分享
- 0
- 好友
- 79
TA的每日心情 | 慵懒 2020-7-12 09:52 |
|---|
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。
+ {* o5 n3 ] _( s/ ?. a! {. |8 [' r1 n% |2 }/ i
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。# Q3 D. x7 W C* w, J
1 K, Z0 Z N/ }3 f v
例如,
7 J' x V$ C4 X* Q F+ A. j& l# S7 i# m8 _' E. n( K
Total = 42
- R3 I' T* C! ^- D& g- E上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。
8 A" f+ j' @3 V& I0 q
; {9 e1 {4 N% o. m" z( sMATLAB中可用的数据类型( X9 I$ d; i3 f( E3 Y, P1 H7 l
2 F5 Z) \! k) m- i5 O% j v0 vMATLAB 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。% r/ v, @- z0 o6 e* [; E
3 R& T1 @7 x, O6 @# d
下表显示了在 MATLAB 中最常用的数据类型:
7 n- k* @& {4 E( y, ~3 [+ b2 a& R& T% j# K" x) w4 L1 e# s! o
数据类型 描述9 P# C. }. L: i3 N! I w% s0 @
int8 8-bit signed integer. I, [" M k* x; r
uint8 8-bit unsigned integer5 h4 F8 N( F' j. Q+ o4 A
int16 16-bit signed integer' G+ R: [) W2 N" W$ [5 i1 d
uint16 16-bit unsigned integer
- D7 @$ Y+ b3 ~% Q8 w, m( Mint32 32-bit signed integer6 `" r7 X; Z, \! e0 L
uint32 32-bit unsigned integer( _( ~5 s3 G# P
int64 64-bit signed integer8 I, e! \6 H0 i3 s6 j. U
uint64 64-bit unsigned integer- t9 H! c* x3 a U9 j3 ?' W
single single precision numerical data3 S' ~. s4 R1 m, ?* x) d6 ^
double double precision numerical data: E3 I: B. E& e/ L2 G7 J. }0 |- H
logical logical values of 1 or 0, represent true and false respectively
* g: g. t$ w3 a/ Pchar character data (strings are stored as vector of characters)
\* v% c0 P7 W! E; A7 Z Ocell array array of indexed cells, each capable of storing an array of a different dimension and data type! ^, k4 a: v1 b. H: A
structure C-like structures, each structure having named fields capable of storing an array of a different dimension and data type
+ w5 l: ]( G' M; R5 p4 [ {0 E; qfunction handle yiibaier to a function
+ N- ]/ b, e2 \7 `$ vuser classes objects constructed from a user-defined class* E7 w2 [: q9 a1 a2 E: A. O, f0 l
java classes objects constructed from a Java class+ O# T; }3 N U. D7 Y- U
例子
. E+ v% K$ |7 Y: _) j! h8 t6 H
U$ \& ]: h4 Q; t2 Y p. @. @创建一个脚本文件,用下面的代码:
. u0 [- X2 R. I# r
" f/ i% u$ a f5 K, i5 k. _. K I str = 'Hello World!'
, Y2 e8 r8 ]+ J; g- d8 d+ ?n = 23455 I& ^9 s$ U# L7 o* S/ E" M! l
d = double(n)& _( }) V7 ^; v5 A& Q Y
un = uint32(789.50)
3 w1 T2 d) M( O0 ^- X) grn = 5678.92347
. ]) b$ p+ J8 G7 v5 Y3 A! Jc = int32(rn)
9 F- _5 ^6 v2 R上面的代码编译和执行时,它会产生以下结果:
& S0 K( m" u& T, b9 L% U6 N* ]# c4 T/ c# z' y) f
str =
a5 w$ n2 O9 h, f* MHello World!( y+ v) [1 d% N+ S1 F9 o
n =8 o2 h1 s! K e# r* Q
2345
+ |" l- ^% y. N' |+ @, U" f cd =3 }% n. N! `2 i# [8 m$ v7 C
2345$ d5 o$ c; ?: F
un =
3 }; |8 ~! n' c 790
; y: q g1 }; J2 q3 P/ C5 f' Drn =; m9 w9 v% A0 {( j3 D
5.6789e+03
* |$ X! [* H: Uc =
1 B! g# Z" v- Y: \7 p& A0 R 5679
+ n2 |6 r, `) f' C4 q数据类型转换! D3 F7 Z+ O0 w' d1 r! |
( f3 O/ h# M$ i# K
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:: W# }+ b* _9 W: {$ N" Z
5 p6 I$ _+ \# G- O7 T c, N
函数 目的/作用& N @. X% B( L/ f
char Convert to character array (string)
b7 z/ v2 Q0 u5 Mint2str Convert integer data to string9 S* Y2 B+ X! _) _) P
mat2str Convert matrix to string5 H* U- Y1 q9 t5 z: Q
num2str Convert number to string
) L: Y* Z% m; w& \% |str2double Convert string to double-precision value- x% m \5 `+ N# Y6 B4 X
str2num Convert string to number
* Z0 B7 S+ D, U' J. }2 C% E9 `, S6 P* dnative2unicode Convert numeric bytes to Unicode characters
- X8 Z' i4 _( Lunicode2native Convert Unicode characters to numeric bytes) N9 j X5 ]& `/ v3 d3 K8 f, L. c6 X
base2dec Convert base N number string to decimal number
, e" J) m+ S" \7 obin2dec Convert binary number string to decimal number9 i5 ~! g* j7 P G# L9 T, r
dec2base Convert decimal to base N number in string" o5 b* X# w( k7 j( A' S8 V& p7 S4 L
dec2bin Convert decimal to binary number in string! {9 H: ]* @* \+ ^9 R& h
dec2hex Convert decimal to hexadecimal number in string
7 m/ f- }: j7 y# b% E. Ohex2dec Convert hexadecimal number string to decimal number5 n7 m& b3 _7 E# O
hex2num Convert hexadecimal number string to double-precision number7 t. @2 C) ]4 |3 j) z: V& z6 }
num2hex Convert singles and doubles to IEEE hexadecimal strings8 s9 Z# q/ F! t: o" i7 H3 f
cell2mat Convert cell array to numeric array
1 i* ~" t/ \5 R; c7 [cell2struct Convert cell array to structure array
7 V% [8 z- ~2 b4 @; y8 Ucellstr Create cell array of strings from character array
* ^( b/ _, w. n) Y/ Pmat2cell Convert array to cell array with potentially different sized cells
: V4 i# d) w1 y, rnum2cell Convert array to cell array with consistently sized cells
+ s+ {* D# ~' }/ M: A! Xstruct2cell Convert structure to cell array9 ^$ U1 I8 r% |; q
测定的数据类型
7 g' \2 t% c* V3 R, L7 j& F. q0 [) ]# K y/ F
MATLAB 提供各种函数标识数据类型的变量。, }: t2 g6 b- C6 z$ G: D
9 R: X, q/ [- `
下表提供了确定一个变量的数据类型的函数:
* M) `( j3 k7 A( U9 c1 r: r" F0 ]- M0 @* c/ U
函数 目的/作用
4 I/ o; x3 @" e1 n- M+ Zis Detect state
S2 r P# y' B7 R- C9 b6 bisa Determine if input is object of specified class& ?% @3 a5 [* t1 n8 s( V# x8 z" M+ Q
iscell Determine whether input is cell array
# a- J* ?) _5 k- Z: I6 h# D" qiscellstr Determine whether input is cell array of strings
8 v) W8 u6 K# [ l2 tischar Determine whether item is character array
# k# P- K# m6 disfield Determine whether input is structure array field& W, x& M) z6 G
isfloat Determine if input is floating-yiibai array( @7 q* g x3 P3 l- B
ishghandle True for Handle Graphics object handles
7 [6 \4 Y j" I, I# W# {7 d0 xisinteger Determine if input is integer array
7 i, o& p6 J/ r# ^8 i9 `- {isjava Determine if input is Java object- o4 a- f* Y" P: ~6 u9 m
islogical Determine if input is logical array
* f% o) C' Y8 R0 P* N& d$ F. yisnumeric Determine if input is numeric array
5 g2 b8 J/ _# i& Wisobject Determine if input is MATLAB object. U% P! `# _* L8 E% }
isreal Check if input is real array9 O9 d3 X5 l1 ^
isscalar Determine whether input is scalar5 q" B8 L2 J- X7 b0 U+ N
isstr Determine whether input is character array+ t5 z* V! z( Z+ `- h, j" b ]
isstruct Determine whether input is structure array
d1 T( a5 j- |- o3 wisvector Determine whether input is vector
: _0 i1 o. S7 F7 m- Lclass Determine class of object
6 U1 H4 h: T f6 J: Xvalidateattributes Check validity of array
# @. N5 T1 b1 K5 J1 e c7 J: C" Jwhos List variables in workspace, with sizes and types2 n F/ [$ D: M6 l8 M
例子, |' h8 p8 M, U# m/ Z$ d, s7 F
; J3 P/ V' Q. p9 J6 Q
创建一个脚本文件,用下面的代码:4 ~* j# ^. M/ G
; T( i# V1 w- H0 {, Bx = 3
8 |2 t J$ P. U$ W/ ?isinteger(x)# B# x7 q/ q! V* k# |( E8 {1 l
isfloat(x)9 Q$ ?" H4 z' W2 W# k
isvector(x)
8 W7 A8 J' Y% [isscalar(x)6 Q i% D) m; r$ o$ C1 h
isnumeric(x)+ t% q8 W' e. F m& g
6 a* p7 w" S3 ]x = 23.54
3 ^" A2 R6 s4 S" U' nisinteger(x)
/ [# n5 K, f1 \isfloat(x)
8 \2 V- N& m3 Jisvector(x)
' h0 ]% J# w2 B: Q+ i7 w% Z; s* e; X1 Bisscalar(x)
) U" W+ g+ M, z* j4 T2 ]isnumeric(x)7 C/ s) D' u. ]6 n5 s- B
2 Z+ a2 G ^ x6 o6 Cx = [1 2 3]
0 G) V, x9 v) ] O0 z9 ]7 w% u. Oisinteger(x)
8 n0 g3 J9 O! S' f2 K+ visfloat(x)( @" ~3 Z$ Q& i8 y
isvector(x)
/ M% U# ~3 e4 S. U( b3 k' Fisscalar(x)
* ^7 s0 O: j, m* E9 e" j/ n p2 b0 `$ {& A/ w
x = 'Hello'6 q8 s' [$ U2 N7 I* [ _' t
isinteger(x)0 [% Q- u/ |4 y O+ R w' i7 v5 v
isfloat(x)
9 u3 U3 x4 d9 xisvector(x)4 v* x% E5 W$ w; H
isscalar(x)" H- c2 G$ o' d) Y5 o. t; B) R
isnumeric(x)
! r0 P& B2 O' `1 K- Y$ ~" } N/ V7 R( M当运行该文件,它会产生以下结果:& m$ }8 a" x2 ?, F* R# F! ]/ {
~/ r' c/ a, {' [x =+ _1 [- E1 p! J" _7 D
3
{ ~0 b5 h6 K$ e3 kans =- v' k0 v1 N) ~/ ?( O+ R0 F6 e
00 n+ H: N# p7 S. R* s# ?2 k. h# y. D
ans =, a9 k" Q5 Z+ F- Y4 n; j
1
0 R: J$ N* l* [( pans =$ q+ P: e! s3 \, F& ]
1; i1 d u; W4 M5 B6 {
ans =! X" x8 u. W7 e$ D% x
1 [5 X d B' J' H2 Z5 Q
ans =3 i. \4 j; v* C' D$ S% z
1
; O4 B/ _/ d+ E" wx =
" h+ {) g8 |8 N* Y0 V% E 23.5400
3 L' o* z6 {* b' Q$ cans =2 |3 e5 X# O2 \) m& W6 Z+ @
0
# L) X; W' t4 _+ s0 n! rans =! c) D2 C& I$ m: L! J
1& s* W+ a' A; K7 d, M
ans =+ ^1 c1 g" _7 l1 `8 `* W; x
1
* }1 T6 G$ u; b1 e+ T/ ~& R6 mans =
$ @+ S" x! ^) s/ ? 1
9 a; w; G& z( r- I7 ^9 W# mans =
9 |# M2 i0 ~8 \" @& W, j* x 1
! m% K1 ~6 e7 bx =
X |& O0 z5 U; f2 H; P% g3 z2 E 1 2 3
+ m7 P+ ~4 Q9 J4 f0 Ians =
. L& X3 f; ]- Q, r! b6 B M 06 V" ^4 f/ N) F" g: Z' {% z* y$ [5 g6 y) _
ans =
4 e/ q4 F3 ~" h' U7 P 1+ l, X" f7 x5 r) v" f3 w( E8 B/ w
ans =
6 J L& {5 y- S5 U7 n" t 1
; @7 T4 M( s M. R# R+ Pans =
( L5 f. Y4 r( |: a/ M 0' g4 G, _1 _. O' Z0 ~& [
x =7 A G+ d. q) f9 R& d1 F1 P
Hello; A/ v+ C& R4 D0 `% `
ans =
% g3 ~, i& v& U 0
- E. A7 F% O: y; \! Uans =/ G, ~% a% Z; H7 Z$ _
0" [% ?: m8 A5 e& [. c
ans =- K' M6 \/ G# F t6 w# N
1
* m! U2 V& u" I7 wans =
; @5 q3 _8 r; G5 O4 A 0
# Y4 g6 j# `& [4 Z2 G9 ?; C: m5 N Fans =
# h$ q: ^$ i6 n) g8 | 01 _4 _$ }# e, P1 z" n
0 g" k% w( s+ H. y# b% B5 ~& Q8 A% Q————————————————
3 ~2 G* X. m0 a版权声明:本文为CSDN博主「Phil__ming」的原创文章。
! K: _7 K+ r1 e7 r. J( @原文链接:https://blog.csdn.net/Poseidon__ming/article/details/75092575
( b. b( M6 m( ^1 u! y
/ m8 v7 X( R/ Z
* Q+ C1 S! e8 D3 O |
zan
|