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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。
& `$ j" N ~% K$ `( f/ |" _2 \6 P8 ~3 @
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。 W) K- Y( w( ]+ |: k% `# M7 G
" V- J$ u7 U1 X" b! J4 Y2 l4 m# u/ A0 l
例如,) O! K F8 Z) O" u7 D0 m7 I
0 h/ v1 @ `) ^+ K J5 b
Total = 42" u, p2 U% Y" ]$ f) k! g
上述语句创建了一个名为“Total” 的 1-1 矩阵存储值42。0 J& I8 u) Q5 M B3 ~) d
! W: H) J$ {2 s3 \; w& S0 t' FMATLAB中可用的数据类型# Y+ \% r% q$ I* w
9 E5 _0 o+ {0 N) Q7 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。
4 X/ Y' W( Y% o+ }
' c1 k* w$ i6 e" Q( q下表显示了在 MATLAB 中最常用的数据类型:# M: f0 t, Q2 x, A
5 B/ p+ d! f! U) h数据类型 描述* p& J+ q. W* n- ~& C
int8 8-bit signed integer
. f4 X; h( |7 Cuint8 8-bit unsigned integer/ `' A: S9 @4 ?* s: i1 l
int16 16-bit signed integer5 x" h9 C% T" v, G) p/ ]. o
uint16 16-bit unsigned integer
3 @' U1 M8 b& ~! a, C" B! j8 jint32 32-bit signed integer* T0 o/ U% e: e8 A, N$ }5 y) V
uint32 32-bit unsigned integer
x/ j. ?9 g7 r. e9 |, e# kint64 64-bit signed integer
3 m6 D. _* u, J7 J: K& K# `; wuint64 64-bit unsigned integer
8 \* X! E8 L% H$ \: fsingle single precision numerical data& n$ D: F1 C) i
double double precision numerical data# Y. U% u x8 d1 O
logical logical values of 1 or 0, represent true and false respectively5 P0 w& T( W/ f% Y- l4 p
char character data (strings are stored as vector of characters)- L: ?- T; f* Q6 t& H; }
cell array array of indexed cells, each capable of storing an array of a different dimension and data type8 ~8 S1 O# ]( x J9 N3 l# n
structure C-like structures, each structure having named fields capable of storing an array of a different dimension and data type1 t: @) T# w5 _) e! ~% m' ~1 d s5 W
function handle yiibaier to a function1 N2 e1 ^3 b. Q$ j$ H
user classes objects constructed from a user-defined class
5 @1 f' w: g% d- G/ B1 Tjava classes objects constructed from a Java class& T% b q2 f4 [* D
例子
. B5 Y$ L7 t. ?) r
5 @( l" s4 f( A" }创建一个脚本文件,用下面的代码:
; P1 X$ X" i' d: V2 W: n3 \. m9 U, u
str = 'Hello World!'/ t% q" v5 o6 `4 o
n = 2345
/ t+ i' y {- X) ? nd = double(n). ~4 r& [. o( v( X' G
un = uint32(789.50)
0 w' x! `; N2 }# ern = 5678.92347
3 n# E0 E, j( }c = int32(rn)
1 B# b! e( m. B C2 w5 F1 ^/ V上面的代码编译和执行时,它会产生以下结果:: {* {% t* t0 ~
% R. j) ^$ \0 @. k1 P
str =
" ]1 f" |% x1 ]" q( IHello World!5 i" n7 i* @' O( N L4 V* U
n =! Q, ?' I: l0 K& j
2345) [9 G& {# J- x R
d =
" u! Y# @ |. J l5 G 2345, E! w, N$ |6 H: j
un =
* P; m& e1 A: t) G0 z1 w0 K 790" g1 O1 ?% S. z( } R
rn =6 N% Y; ]- n6 B$ C% b
5.6789e+039 L, d" C, L; k3 X9 _+ q
c =) p f, }8 n8 p. j& V6 ~7 Q
5679
( ]) j, ]- U; @8 O$ } y+ }/ [数据类型转换( U1 c* c6 q) ^" `- Z
3 Z3 b4 A$ u/ u& D6 F5 `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:
* K# }# M( a+ T; |4 E6 }. [
7 A, P" k. ?: K函数 目的/作用$ m" |) {6 S0 u9 w5 e. z
char Convert to character array (string)
- e6 {+ U4 {8 R$ `8 Kint2str Convert integer data to string1 ?& R* `( y" T* b/ B
mat2str Convert matrix to string- y. |4 }+ Y* [
num2str Convert number to string# T) P6 v8 G4 _* I# P5 {
str2double Convert string to double-precision value8 R0 H K( o. s" [$ G( H3 X
str2num Convert string to number j9 g8 Z9 ^; ?; k, Z
native2unicode Convert numeric bytes to Unicode characters
- I( k# T5 n' H; r# r5 Xunicode2native Convert Unicode characters to numeric bytes
: J v( Z0 T4 g9 Zbase2dec Convert base N number string to decimal number
) g8 @0 x' K, d& {8 l2 c, _% ibin2dec Convert binary number string to decimal number- m3 R5 E; z* s7 ~, j6 R
dec2base Convert decimal to base N number in string- C& w$ ?! P1 O, e4 z0 X/ t; A, n A
dec2bin Convert decimal to binary number in string
9 G/ I, K9 F' }/ xdec2hex Convert decimal to hexadecimal number in string3 p6 q4 k+ F9 j8 b, @
hex2dec Convert hexadecimal number string to decimal number6 j4 ]9 s- }5 k! i4 q
hex2num Convert hexadecimal number string to double-precision number8 W; P# L$ l/ [0 b
num2hex Convert singles and doubles to IEEE hexadecimal strings
, _2 _% m8 c3 n9 i( n# s5 ?cell2mat Convert cell array to numeric array" Z! I: D V+ K+ E- K
cell2struct Convert cell array to structure array- f' |! L, I1 Y0 r
cellstr Create cell array of strings from character array
9 _; o- y: ]- {. F7 }6 I0 {) tmat2cell Convert array to cell array with potentially different sized cells0 ~, O* B- o, K1 z% I
num2cell Convert array to cell array with consistently sized cells
/ T) P5 I- \' ustruct2cell Convert structure to cell array
: l' V7 M- |1 a3 o( s测定的数据类型
6 w( [- c# t# Y! a/ w9 Z5 a; c+ ?' A" @; Y9 ^+ j- w% [% U
MATLAB 提供各种函数标识数据类型的变量。- m0 m1 M( S& j/ d( q
0 X4 ]5 N+ ? o0 _6 h下表提供了确定一个变量的数据类型的函数:8 O9 i, ^8 U1 Y. n, q/ T
% T! X6 H$ [1 B, [) M; O
函数 目的/作用
w( O% r0 n% h( N9 Qis Detect state* t/ ~ y' K0 u- {! J/ r
isa Determine if input is object of specified class$ |$ u" z9 N2 v- [+ i1 a. J6 a" o5 B
iscell Determine whether input is cell array
3 c9 z3 V) T3 E# T0 Wiscellstr Determine whether input is cell array of strings: a! W" N- P/ j0 A/ L- O) [( M+ b
ischar Determine whether item is character array& R% T; Y" X# r2 A7 K! p" b
isfield Determine whether input is structure array field3 k1 X- G/ m+ f% N
isfloat Determine if input is floating-yiibai array
! o0 d; m/ t4 ~8 Nishghandle True for Handle Graphics object handles* Y0 _% |- N/ y" Y3 l5 I
isinteger Determine if input is integer array
Z) P6 Q1 U( L$ @# z6 P6 Q, n3 c* bisjava Determine if input is Java object
P9 s9 S/ J7 e0 j- R* E2 vislogical Determine if input is logical array
4 K- @3 Q: r; o4 S) |1 G+ J3 Wisnumeric Determine if input is numeric array' P3 u& d% ~& C R. t
isobject Determine if input is MATLAB object6 k2 N+ }! W; t) V3 v0 K
isreal Check if input is real array9 q# p8 p4 T" w9 D8 V1 f; j
isscalar Determine whether input is scalar- `7 ]1 E7 W. I: K
isstr Determine whether input is character array4 P% Y" B5 C% m& w# e8 x
isstruct Determine whether input is structure array2 x5 `1 r' s4 v# |8 n
isvector Determine whether input is vector
" [2 v( x0 h8 p+ q2 Gclass Determine class of object
" @* I e U! B/ D3 n0 d) xvalidateattributes Check validity of array2 D9 v7 [$ j. ?: j6 S; @6 u
whos List variables in workspace, with sizes and types! B+ Q; f1 s/ [8 Y, z
例子
# X1 [6 ?1 ]1 X
/ K$ Z5 [- p( l% J创建一个脚本文件,用下面的代码:
- F+ `9 p" [; D9 i
# n2 l! t6 h1 _* @1 t' t5 o% t: nx = 34 r7 t. d% H, c2 D
isinteger(x)
2 I7 ]" G! X% z* Y4 wisfloat(x)( i1 j. {4 w! d" K' L
isvector(x)
0 p+ o, J. C! b' H" x r( xisscalar(x)4 N& Y3 D% d0 O9 }
isnumeric(x)
- c" O( {/ L3 h! f! o. @/ I3 \6 L! [' [6 T( W
x = 23.54
& i) o4 L/ T# p) {isinteger(x)
6 m7 o0 Q9 P5 y( | e2 risfloat(x)
' z, s* d, t, f) C% _$ oisvector(x)
) q9 U# d6 ^+ I7 kisscalar(x)
& h+ q4 m8 u( B/ I7 }isnumeric(x)
& z# G) Z/ b) e% c- ?4 v/ F% J2 N8 ]
x = [1 2 3]( O0 [7 h9 x) v6 d' i
isinteger(x)
1 `+ ^; h. A1 I) g' }3 [, A; |) sisfloat(x)9 J8 b" W8 O% H# \, Z
isvector(x)" Z9 U+ g- Q! u/ z1 v- T
isscalar(x)
* O, e( z6 m, f4 K2 n7 p- O5 \1 O
x = 'Hello'1 a6 M: X. N' u' p, ?
isinteger(x)
" Z) D' r7 ~9 [' {- nisfloat(x)' z8 [' P! j2 Q! _8 V
isvector(x)! w) u, z. G C4 K1 @6 ?
isscalar(x)
& H0 e0 y3 L1 q; o4 a9 I4 K6 Disnumeric(x)6 r8 I- @! |% W/ F. \
当运行该文件,它会产生以下结果:
6 v/ @: C0 u* Z+ H8 ^
5 h" W$ a; B1 Y/ c' w# S( fx = R+ n* Q- U y1 m
3, g U, q5 R( F6 B; k
ans =' C% W3 v$ b0 w' q! k; n
06 U$ \9 q) s( W e
ans =
8 ^4 B6 f. b$ k5 [/ T8 U# m 1
/ _7 T6 L+ h6 y, O5 Kans =
6 I4 M% D; F/ J+ ?' b! ] 1
# \5 Q0 b) c) h8 m8 e, s; ^1 Tans =6 t4 K! P j0 x. D# x
1
3 y& \/ g- e3 Q( F, B" K: y0 jans =) F! b! U, f7 w0 I2 K5 ?( e
1/ i, U6 t2 @4 p5 E# j" y/ u
x =- }- ^; B' `/ P* x! |; M/ e
23.5400" ?! X) @: u, ~4 A7 v0 s
ans =: P+ a/ h- Z6 Q" q( R; @* n
03 C- Y5 d" ?! B; _: ]' C
ans =' {: N+ [5 P. Q( ^3 y
1
) ^# U |& p8 L" d8 h; Rans =, p3 d* {9 p# Y, j% _, A
1) e5 t! _$ b' A4 ?4 x
ans =4 z: D! q5 b: ]2 G
1
! d2 u. \3 T* I: s& ?ans =4 ^* N$ i! R- a6 h: c# {* }' f8 U- E
1
% ]- V' _( Y- s; J' \8 `x =' n' P4 h G& K0 O0 k* N5 r
1 2 39 r" p) K/ L' E- | u5 j2 }) S
ans =
1 L2 v* T) v& |1 M! o0 A; b 0! \: X' T. p; A0 q
ans =* ^( k3 r, ~' O* B. f
1: @& M$ U Y1 y2 ]" p
ans =
% c9 M( @9 G' ?( O0 q; F3 P9 q/ \ 1% o) r0 Q$ J' v- s# F5 R! z P+ j, ?& h8 w
ans =7 U1 H- F' n5 H8 P+ \
0
l/ H u% Q. I4 b9 g7 T$ kx =
0 B9 M1 F- j$ U$ j& HHello( ?' r. R# y1 a
ans =- s, `7 u2 {8 g, W) u4 R
0, h( a9 l% M0 \# R, H. {( ^
ans =) {, N: n! Y; `# P! M- X J3 c
0
# V( ?' G5 H$ x4 oans =" S$ U& e* C, @; M# q0 q- H
14 n) f4 m+ ]5 ^! w5 v8 o- ?8 A8 q
ans =1 V0 H" c# Q0 l& }$ i
0' a) h/ ?. C; v. C& d' \! x% V5 T
ans =
: ~& u2 W* n. v+ [2 C 0
1 f' v8 M. d4 J- W, y: I# m
; V/ K) X; X5 `2 [0 i# Z————————————————
7 K3 {; F* K- I% f+ i版权声明:本文为CSDN博主「Phil__ming」的原创文章。
j- q+ @9 T. p; [; T0 t" @原文链接:https://blog.csdn.net/Poseidon__ming/article/details/75092575
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