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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。
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' Z, c( t; H5 C* L; t. C1 r* o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。
7 Q, ?) c1 y# e3 W
- o* [! P) y" r% }例如,; T8 V# C3 n& v; f
+ @7 P0 S. i) F5 hTotal = 42
3 h/ K$ X! W$ v/ P上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。0 \: y: ~# X. H
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MATLAB中可用的数据类型% Z0 e: f1 l% t5 L* H3 K2 `
. Y+ k" R& x# V4 N$ rMATLAB 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:$ ? q G! ?. m3 F. e
. I& h9 g: e: X数据类型 描述
0 Y6 Z* ]3 C4 s% Y gint8 8-bit signed integer
- P: a: N6 G8 |: [; {uint8 8-bit unsigned integer
- G' r- \$ @* Q9 ]9 xint16 16-bit signed integer
& @( X7 f+ Y; w( Y8 xuint16 16-bit unsigned integer7 Q l4 S/ m- @
int32 32-bit signed integer8 ~$ U5 ~; b- B( v
uint32 32-bit unsigned integer. Y) ?" j( R! S; _1 H& o" t) h
int64 64-bit signed integer$ o& `) W, |% U& S
uint64 64-bit unsigned integer
9 {6 n6 r( p0 x$ J1 Jsingle single precision numerical data2 c8 P4 _/ }0 a
double double precision numerical data0 z6 l4 [. {! R8 J
logical logical values of 1 or 0, represent true and false respectively
4 ?7 U/ f- | e* }char character data (strings are stored as vector of characters)! H5 g# @: ~+ W" q
cell array array of indexed cells, each capable of storing an array of a different dimension and data type+ g7 u: o6 ^; j F
structure C-like structures, each structure having named fields capable of storing an array of a different dimension and data type3 s" j" f) D, v& `, |$ y# W5 G4 ]* U
function handle yiibaier to a function% z: M, G) l( V
user classes objects constructed from a user-defined class8 b, ]$ @5 k, t7 G' @
java classes objects constructed from a Java class
% i) \8 C# p- i: X9 c例子5 ~+ G6 i1 d& X4 g
! A" ~) A8 D' t: f" a9 i
创建一个脚本文件,用下面的代码:
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str = 'Hello World!'
+ Q- ]0 [5 O/ S/ rn = 23452 H5 V5 k8 c3 C) ~$ f
d = double(n)# T( N+ ?# i: D Q
un = uint32(789.50)
]6 v @8 l& C# e$ p* H3 F4 crn = 5678.923471 W, X a; E0 H F! U
c = int32(rn)
! H O W' }; ]上面的代码编译和执行时,它会产生以下结果:
: W( e) m- [: Z. Z" o* }4 \) D' c; o; K5 Q" X- Q: k# n% Y( R
str =8 M) j/ ~4 z7 C: A9 ^- |' H
Hello World!. u& B, Z' k* x( y4 A `
n =8 \7 \4 {, o4 k. N# T
2345/ o( ~, M2 c( c/ O4 q
d =
5 h; e6 W5 S/ h6 d; [7 U 2345& ~' R5 [1 N+ B! `$ T9 d- D% `
un =
/ |. ^' ]4 A }/ y( q9 ` 790
5 M6 G- C; i" p/ Hrn =
3 _$ F* G6 _& H: Q) y( b 5.6789e+03* N. g# u+ W0 @% J
c =* b7 b" g7 F+ V' C' S. {4 w
5679
1 }. Q1 \1 J% `& D! f: A数据类型转换
g) @( x! z( [# i( g
7 K7 f1 y! ? PMATLAB 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:3 I- z/ W7 o) M7 h9 k
5 x8 S: D9 x) Q4 f1 X. ~
函数 目的/作用3 f$ h0 ^) P( [. ?3 E/ ?5 b" O
char Convert to character array (string)* p3 e, R" V- ~5 I3 \
int2str Convert integer data to string! U" T& ~7 g! @5 W+ F
mat2str Convert matrix to string3 ^7 Z! a4 }, \" R) K- j+ r
num2str Convert number to string1 D- J: Q. F* Z. N- t% p( G
str2double Convert string to double-precision value
& [ x* Z' x9 x) ]- Cstr2num Convert string to number6 C8 s0 x+ _: ~4 c/ F& i/ X* |; `! I
native2unicode Convert numeric bytes to Unicode characters
: X# _% D/ S6 eunicode2native Convert Unicode characters to numeric bytes" p* m- ]$ r2 P1 V( }: P3 W6 ]
base2dec Convert base N number string to decimal number
: r$ w) B% ]& O7 v- Z1 o5 x- Xbin2dec Convert binary number string to decimal number) b+ f/ P" W$ T u/ y
dec2base Convert decimal to base N number in string0 w/ W& A/ w' W$ P" h# X
dec2bin Convert decimal to binary number in string/ j. N; C2 D4 `8 Z0 X; `% b1 ~
dec2hex Convert decimal to hexadecimal number in string
5 K: S7 D& h3 p0 p, U* ~( }hex2dec Convert hexadecimal number string to decimal number
4 W7 \& x6 Q' W3 t( Y4 Shex2num Convert hexadecimal number string to double-precision number8 A! g8 \3 ^% G0 P2 h1 s) w8 p
num2hex Convert singles and doubles to IEEE hexadecimal strings
, x2 v% E: @7 P T7 y8 scell2mat Convert cell array to numeric array: X c# s) c" D3 A
cell2struct Convert cell array to structure array
$ _" a/ a7 A; {3 ?$ {+ P( _cellstr Create cell array of strings from character array
# m$ ] p3 j" G [9 L& Dmat2cell Convert array to cell array with potentially different sized cells2 T+ H% B9 K2 V# p
num2cell Convert array to cell array with consistently sized cells
! b/ x3 s4 g+ l( n+ Kstruct2cell Convert structure to cell array8 E) x. \! c3 `
测定的数据类型
7 s, h, q# V* ^5 d% W
! v1 E3 x* l* aMATLAB 提供各种函数标识数据类型的变量。, r0 B/ b! D/ |2 R- n! c, s- C
! U, t" `! Z; V" ^; F下表提供了确定一个变量的数据类型的函数:! O) q; Z6 n O' ^
9 [) ~) [) P" U2 C8 h E
函数 目的/作用1 G/ R% U$ ^2 e! S
is Detect state2 Z! _2 m% X9 U3 l' c V
isa Determine if input is object of specified class9 T$ r* k. ~8 o$ z; `
iscell Determine whether input is cell array; @) T, i5 ?/ P3 o8 _
iscellstr Determine whether input is cell array of strings! \3 [' A( E! P- k( a9 {
ischar Determine whether item is character array1 F* r8 Y# K) k% C" y A/ F
isfield Determine whether input is structure array field
1 C/ R" K7 j$ Misfloat Determine if input is floating-yiibai array
6 v3 L3 h! G& \/ Tishghandle True for Handle Graphics object handles
e! K4 |/ w2 H- `9 `) ?: A Gisinteger Determine if input is integer array: ]0 |- o0 |% f. m/ ]4 U
isjava Determine if input is Java object3 ?; H. Z) C& x3 Z1 ?
islogical Determine if input is logical array
2 O$ q7 j1 g" o$ z- G/ I% P1 e3 jisnumeric Determine if input is numeric array1 Q' Z7 H V+ \0 M( r* C- E
isobject Determine if input is MATLAB object
4 E" H. H/ S9 j. k1 p! f3 eisreal Check if input is real array7 j& d* [% v/ m! [
isscalar Determine whether input is scalar- Z; O3 ?6 i* `+ W# ]3 m
isstr Determine whether input is character array
' x6 L& E+ W" \2 [/ J/ N* Iisstruct Determine whether input is structure array
) X, P, R/ ^' \' O" B" c4 F# | \isvector Determine whether input is vector5 N1 d' B( F! M$ B& G2 b+ C& ^
class Determine class of object
$ \7 d# w h$ s4 m7 Hvalidateattributes Check validity of array- b: R( r) Z' o$ v
whos List variables in workspace, with sizes and types: |) e3 b( e" D! G9 T
例子
1 f7 r* n3 L% r' t. h0 {5 {% z9 ]. O9 q* X$ t3 _
创建一个脚本文件,用下面的代码:
2 M6 A2 C! F: s8 F' B6 o) `) @, q; z- d' X
x = 3
L2 ]" s: O- ~9 n' Disinteger(x)7 {9 N8 ^5 B9 i' u, ?4 g
isfloat(x). M" ?/ w0 m% X: G0 \
isvector(x)) M+ z3 k/ k+ p! }$ t( B0 f
isscalar(x)
9 `1 n# O" Y6 }isnumeric(x)
# t1 h- X& E# s4 h) ~# U' D
9 [+ s j6 i0 G: f. ^x = 23.54
8 R% r% `! S1 ~7 x/ sisinteger(x)7 J- i w4 B( q4 ]! N2 w' m- c$ y/ g
isfloat(x)2 c1 u$ M# b% u/ {9 N7 D# y
isvector(x)( B7 F' K, {( O Y/ ]9 M
isscalar(x)
. G5 u5 Y% j+ h% B2 u: k0 Y( ~isnumeric(x)
' ^* o" X A) ^& u4 D2 i6 n2 p1 J8 _0 ]8 B$ T
x = [1 2 3], R0 D+ L! e; F1 p* {, k
isinteger(x)
; j/ i9 V( b/ b( b+ B; {isfloat(x)
5 K" l7 p2 l& z8 i5 Lisvector(x)
+ P% y3 L, J& ^* T- Yisscalar(x)
+ U& x4 c6 c% }6 ?* Y
! u4 @8 L j" F+ R- |x = 'Hello'/ _+ }1 R+ M' a2 V7 v% A6 v& o6 P
isinteger(x)! u5 {: ?; l3 _' V* d
isfloat(x)
% {' l4 u4 @+ L* P7 O# g& ]. ?isvector(x)
% P" \' v9 {) ?- ^! f# K! u3 ?$ E, eisscalar(x)
, k$ s, q6 z9 d; I- | Nisnumeric(x)' j- B) q( s. s- A) F
当运行该文件,它会产生以下结果:* E5 S2 S. N9 B* E% T6 J3 l9 i& a
+ P+ B1 M# z' Z' ?7 _x =
6 n# l7 M/ h; u$ R! V 3
0 s ~. q% `9 ^ans =
$ Z" `0 R: t6 { 03 J7 u' t7 Z0 u: d0 R
ans =
( @! m2 `, L* J- d5 j- A 1, N& Y% u$ ^- Z6 ?8 E
ans =+ m, p+ e2 K% A' \6 ~( o# H( v
1
* D& A3 {+ @0 e7 Bans =+ ~* @4 h; X: E+ @
1
& x& G* j. s1 F3 h [& i' {( qans =
/ N5 Z3 d5 s$ i- L 1; z- l7 V( i0 ^. ]- O# Q+ N1 n
x =. W* Q9 R0 i, C' ]) v
23.5400
$ z. q7 A/ L2 N5 L; aans =
8 @- t: b/ V3 D% c# n5 i 0* u( ^' a, F0 u6 N; J6 |
ans =
. _+ p' q5 i9 r, o( |. ]( p 1
5 x2 _: Y$ U( N! z. Wans =
* q$ z/ q2 E h2 @$ a 11 f5 Y3 g% _' U% J
ans =
$ X" }: Y' w# N 1
. O7 K7 ?: w! M* d, Mans =
% S, \7 A3 ^& ~3 o }2 D4 {* Q 1+ R# [- n" h. N) c$ {
x =
; v0 r5 G) d8 z) Q$ ? 1 2 3
9 e6 X& H- t6 r0 E: qans =' L# m) Q1 C H! @0 \) S" i; v( v
0' a0 ~2 u& X0 k: |0 v$ R
ans =
+ n8 V3 S$ R# D/ B0 T 1
& w! W3 m! R2 @: J' h8 l* jans =
- C2 W: F/ H( ~$ G% q( J1 S 1# c5 b0 m4 H z! }
ans =
! g& U# F# i7 c, @ 0
, T% p$ L# v( Ex =
x: H! X+ E/ WHello9 J! |, R( t; x: A' g3 i$ e6 z
ans =
) J# l# ~$ t& H, k1 k% G* j, F 0
$ @# L# a& D# m7 a1 A" lans =
. ^' w% D B3 N) ^8 t+ A8 P1 P 0
! v' I; `1 c1 X1 W& Oans =% F. L& s0 k$ `0 g5 l. |% f4 w
1
. W; i3 a7 q F0 U$ t2 Y! [ans =( F7 i$ ?4 J; q
0 ~& ?, r7 Z& X! j* R2 A
ans = Z* E* q$ Z' G; w0 G/ T
0& _6 w& w/ g( l' {8 @' {
$ r, O9 I n9 ` y% u
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8 y+ o- Z, R8 |( t$ h" \; ?版权声明:本文为CSDN博主「Phil__ming」的原创文章。; ~) s& X# m0 S9 }
原文链接:https://blog.csdn.net/Poseidon__ming/article/details/75092575
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