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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。/ `. l9 j' f; x* u
3 k; X( [8 e) f+ ~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。
& J4 w6 E1 F5 Q" r2 j$ u* n; P
$ c1 h% _" q ^ d' {例如, E1 N* a% X) i
1 a7 l, y* k' UTotal = 42
$ V- k- `3 e4 I( K u6 w上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。# v) g, e: d) o5 l3 u2 N f+ S+ Z7 _6 k
' ]% [& u" {2 g* k# V1 Z7 [
MATLAB中可用的数据类型# M* y- p2 b8 E3 F& m7 R, T- X
7 W; f4 W E+ L8 ]5 a( e, m) ZMATLAB 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。
U, k. K$ p# X. D1 ^! i6 y
1 {' _- c" m& y3 Z' ?7 H6 w下表显示了在 MATLAB 中最常用的数据类型:+ w! |% G6 O; O9 |
4 | ^% v' X9 P+ G1 g
数据类型 描述
2 y! w8 F7 L" j5 v# lint8 8-bit signed integer7 W5 A1 W9 T r0 s9 L+ p% Q
uint8 8-bit unsigned integer
2 ~4 k$ Q$ |2 E0 \/ yint16 16-bit signed integer. M, X9 Z |0 x o' K) y
uint16 16-bit unsigned integer! D/ \4 A/ Y* O
int32 32-bit signed integer/ d, `; H0 D% r8 F, ? `
uint32 32-bit unsigned integer
0 } F1 R5 W8 rint64 64-bit signed integer5 c$ j+ `7 y! M" |. C' g
uint64 64-bit unsigned integer: P$ o8 P' @) X5 f
single single precision numerical data0 Y, l/ U5 h* B
double double precision numerical data) @4 ?/ M1 ?2 B( v0 x" I, m
logical logical values of 1 or 0, represent true and false respectively
+ [: M$ D1 H2 H# _char character data (strings are stored as vector of characters) R6 {9 v: Q( E" `% b% l) V
cell array array of indexed cells, each capable of storing an array of a different dimension and data type7 `' a% G+ Y0 _9 ]6 ~/ f! x( ]
structure C-like structures, each structure having named fields capable of storing an array of a different dimension and data type# D4 g: @* w) Z2 }- U# P" K
function handle yiibaier to a function
$ L: ^: t; c6 m4 X- n( ?$ ouser classes objects constructed from a user-defined class
8 j& b5 e W1 Mjava classes objects constructed from a Java class3 v7 I" S- o) b7 l9 c" Y
例子
" P ^7 |, t! W( B
/ e4 ^' [* v. B7 g* X创建一个脚本文件,用下面的代码:
, Q+ f4 a! C! s1 m/ w% s+ M$ K* m* I" o
str = 'Hello World!'& c) c! b5 c7 p: p( o3 s1 ]
n = 23452 D i6 i; L2 r+ T, S
d = double(n)
A" l$ _- k. Vun = uint32(789.50)2 `. [# F7 R8 M4 u% ]; E
rn = 5678.92347
5 @2 C4 w# g. @/ Gc = int32(rn)
, K9 K+ f8 C1 A% j6 [8 D上面的代码编译和执行时,它会产生以下结果:
9 d; B6 h: u( q( p6 b
* S& U6 Q) C ^# _9 P' g! tstr =$ {$ g# X: i: t# }
Hello World!. C0 q+ q9 g/ e- Z. `( ?
n =
. d; B$ I3 K+ |$ ?" N3 G 2345
* @: e! _- F, [' o4 S" `/ Sd =
$ A: l0 u: L9 t3 x# X4 ^4 d 2345: j1 L% @5 W) M$ `0 [7 z3 b3 z; g
un =% X* I! m ?4 X3 q3 c6 }
790
2 q$ w7 U9 C3 U. G. l5 u- Prn =
# {/ ?' E8 B1 X1 k 5.6789e+03# }5 X6 i, N4 m, m! a
c =
* t. j# ]2 j/ n- a# Q 5679% h1 j. C( {0 z" f5 u8 x
数据类型转换
" ?, X) {' B4 k
' i; ^; e$ X( y/ `; g. I3 i+ KMATLAB 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:
1 H0 R3 @1 g8 z) [! Z
" T8 M6 t# N: K+ p4 n7 s1 v函数 目的/作用, `* X2 Q) h9 y5 K* @
char Convert to character array (string)' C2 @/ A! C' s6 t9 A: v7 l
int2str Convert integer data to string1 c& t6 q$ ?0 Z% _5 R8 ?$ S3 U+ B
mat2str Convert matrix to string+ t6 ^6 }3 F( B; |) a- K
num2str Convert number to string
6 Q" G4 H1 M7 x9 t( ~3 gstr2double Convert string to double-precision value
/ R2 ?& n1 ]) l vstr2num Convert string to number
! \) @3 D0 o% O# o L5 Inative2unicode Convert numeric bytes to Unicode characters: V2 N7 v! b& [4 U$ h( q
unicode2native Convert Unicode characters to numeric bytes
/ H" N- E) g7 i% z' M$ Hbase2dec Convert base N number string to decimal number
F _4 S) J- Q$ Obin2dec Convert binary number string to decimal number
+ `6 k* y8 S! Q/ K' y/ F6 S2 \dec2base Convert decimal to base N number in string
7 O. X( O1 F& K6 L+ O6 t& l( D: xdec2bin Convert decimal to binary number in string
2 [& W! O+ ~4 _8 m# N3 }8 P8 cdec2hex Convert decimal to hexadecimal number in string5 Q) `. \- |/ M+ ]% w$ h+ y
hex2dec Convert hexadecimal number string to decimal number
0 K4 T `7 C Q/ [9 ghex2num Convert hexadecimal number string to double-precision number
5 l/ z$ w* L7 d L* bnum2hex Convert singles and doubles to IEEE hexadecimal strings
& y# a/ L+ b& T( r9 k6 t( O; j% F/ @cell2mat Convert cell array to numeric array
: I4 {& q( G' K1 f0 P1 scell2struct Convert cell array to structure array
h! h' S. ?# f0 xcellstr Create cell array of strings from character array
' i1 j0 v: c L Wmat2cell Convert array to cell array with potentially different sized cells) ?0 [& G) m2 D& @
num2cell Convert array to cell array with consistently sized cells2 u0 d' I8 y' W' p5 y/ p, f
struct2cell Convert structure to cell array6 k3 z! k9 G/ J; f
测定的数据类型
3 O* {. [9 K5 E; Q
% ?2 a* P: t( v$ t8 a H( SMATLAB 提供各种函数标识数据类型的变量。& w, B" H) Z0 n3 z2 \9 X! ]& K* o
$ _3 O7 |/ x, z1 b7 c. F
下表提供了确定一个变量的数据类型的函数:
e/ u& n Z! {% N6 _( Z3 t% H2 V. C" ~1 k+ A. W3 \
函数 目的/作用
9 Q5 d1 P% N+ ~. `1 k+ M' Lis Detect state" J" H C+ B! o8 Q* t* [
isa Determine if input is object of specified class: V+ U6 I! F2 h( X
iscell Determine whether input is cell array
; N# O2 R+ \2 E% N7 n8 Miscellstr Determine whether input is cell array of strings" z# E9 ^2 S% J
ischar Determine whether item is character array/ I' h. C( d3 n2 K3 K
isfield Determine whether input is structure array field
# {0 W, a5 W! @$ h& l; x0 `isfloat Determine if input is floating-yiibai array8 m: |4 Y, e, p! O/ m
ishghandle True for Handle Graphics object handles
. a: v, q4 m5 Q7 z1 |isinteger Determine if input is integer array
6 n, _0 `+ F3 u$ r8 Q- |2 ?' pisjava Determine if input is Java object
1 u; v* B& |4 R5 i6 A4 Oislogical Determine if input is logical array# Z% O- [ G; y1 B+ p0 G
isnumeric Determine if input is numeric array
5 q/ B4 c/ a1 _! Aisobject Determine if input is MATLAB object
8 V; j7 {4 w- ~" _. {isreal Check if input is real array: U" g, h! r9 p% h+ p
isscalar Determine whether input is scalar
b m5 `7 A) k0 }4 zisstr Determine whether input is character array& J; x% H ^5 G5 e5 v
isstruct Determine whether input is structure array
4 {4 w5 V# P, ]" u& k; R; j* _1 S. Qisvector Determine whether input is vector
( @/ c* c; J& G) a8 qclass Determine class of object
) W, {6 G$ J- _: yvalidateattributes Check validity of array; p' j1 _8 ]5 u8 R. @/ d/ y
whos List variables in workspace, with sizes and types4 S ^3 |/ n4 I' v# ?7 c
例子
: t" A1 `) C( X1 v/ b4 h; V0 T0 u& z' w
创建一个脚本文件,用下面的代码: s s- k& E. O# F$ {5 _% }
) F2 F# C' x" z, J
x = 3% d4 U% L+ R' z ^
isinteger(x)2 }; f8 o, Z& E+ `0 j# y0 q
isfloat(x)2 x' ~. [% Q; f, g) a
isvector(x)- ]7 A/ }7 Q. {7 C* D& @
isscalar(x). @% ]& I! y& r1 p. L8 [
isnumeric(x)* p& C7 ?* h% v" ^. D
% T3 F' |; r# t8 o- M
x = 23.546 H4 X2 V' {/ j7 ?# R, i
isinteger(x)
) p4 l) f8 _8 q8 S9 fisfloat(x)6 g* I% ^# F/ e3 O* m/ p+ v" h
isvector(x)
/ j8 k) u% c; e' Pisscalar(x)0 B- X' O, C3 D1 G% A
isnumeric(x)
" g6 t: l/ b! _- z) M' @
" U% ^' V$ d, {5 A) ix = [1 2 3]
9 t) \. L4 |) Y' f! cisinteger(x)
+ p8 p. ]0 [6 {8 {- sisfloat(x)
* k. Q1 `3 x# Gisvector(x)2 V T) _' a: m% G" A, ]! L: _( W2 R
isscalar(x)
( j" X6 W( ^; a
" V$ R! n, G( w. ^" sx = 'Hello'
7 s$ Q/ H/ w' l# qisinteger(x)4 L- T% H" \9 ]; a$ X# \% G) z
isfloat(x)+ k0 H: C6 M# ?; o+ G+ n: o2 o8 h2 v
isvector(x)
% L8 D, ~) r2 E& n% _4 Yisscalar(x)
/ q, `5 Y5 M2 j" Z9 Aisnumeric(x)
. R: u5 V1 U3 Z& j6 h8 t# v当运行该文件,它会产生以下结果:
, D! r" d$ z; E# i) {5 L0 N. ]
2 q% P t+ |2 H( Hx =
& _, h; f* j: R2 U; Y 3$ K; n# P+ r, j# [# n3 F
ans =& V1 A0 J; C2 \+ a' t$ m0 e+ u
0/ H, Y- j# P. p$ Q& R
ans =
4 [0 y9 |8 Z. N5 {7 b4 N" L 1
0 v6 a- S. l+ b) |) I" l1 O8 _ans =
8 X: s2 Y+ M1 G$ c2 ? S. n 1, H8 t5 }' l8 P' h
ans =
E6 a7 C+ i" `! K5 k1 G |6 d 1
( }& T2 z/ L$ `6 S" r( @* mans =
2 q8 {9 {2 Z# p 1
) a! Y1 T' g% |! b8 c" R* Hx =- |4 {# }2 |, w$ p
23.5400
; ?( ]5 z- \$ S' a. U! k8 d( a6 q% S) Oans =
4 s+ Q' B) \, y6 u7 q 0
0 D: A" [* `# Kans =0 M2 T+ [1 g8 f3 L. q+ u% C- w
1; A- G( \4 Q2 I e; y9 R/ D
ans =0 h8 k3 s g# h! ^+ I* _. v
1* ]3 V" y; N8 Y5 ~8 n9 H
ans =9 I& l* B+ s7 O! Q
1. {4 ^# Y) k% c7 u
ans =! \7 F, _& V& f1 O2 r
10 ^# ]* T% q/ ]& x4 O- i
x =$ z2 s; h* [! W# ]8 P* k4 K
1 2 3/ W b7 K4 e; [9 ?* v. H$ @, S
ans =
4 E) c; X ]9 J4 U1 ` 0; Q q; |* E, X2 o
ans =
3 J5 K2 ]% l% z1 g 17 j. o7 o' y1 J/ ?: G
ans =
/ Z" L; q6 M, t) B7 r3 S9 v& y! R 1 U5 Q0 V' y2 u* C3 t6 z
ans =
# \" C. \$ F2 F- a. r7 w8 O a 0/ ^8 ?4 |; i/ A! o
x =
/ v6 y% S3 I7 R' BHello/ Y5 j- {( B4 i) A. X
ans =7 y+ ~- K, X# i1 Y: K+ H
0) u2 u& t0 H$ D( [, v3 k# O$ n
ans =
! M2 y" u8 V& z! S7 f5 I 0
' {$ G2 h" d+ m' Q5 H4 Dans =
* ~# u0 @4 H2 R' O: Z9 j2 q 1
% O0 c( M0 b( O; ?, ?ans =
7 \( }+ p2 r: M 0
" Y, D3 w& Y& Y0 \0 J3 yans =
. {. Y+ @* o" W4 y* K- H' D 0
! N/ w) ?7 e2 o d ^; Q7 P( K. [2 a4 E) L! c# @6 c, ~' l
————————————————+ u7 c6 V; _8 x! e- s( g4 _0 r
版权声明:本文为CSDN博主「Phil__ming」的原创文章。
* d7 A# @7 T0 J9 E原文链接:https://blog.csdn.net/Poseidon__ming/article/details/75092575( v2 B5 x' b3 s$ V% F8 X! e% n2 J
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