Matlab中如何用多个数组元素做索引 matlab中如何找到数组中某个数值的索引的问题
matlab\u4e2d\u5982\u4f55\u5229\u7528\u5411\u91cf\u4f5c\u4e3a\u77e9\u9635\u7d22\u5f15\u8bbf\u95ee\u76f8\u5e94\u5143\u7d20n\u7ef4\u77e9\u9635\u6709\u4e24\u4e2a\u4e0b\u6807\uff0cn\u7ef4\u5411\u91cf\u53ea\u80fd\u63d0\u4f9b\u4e00\u4e2a\u4e0b\u6807\u3002\u5f53\u7136\u4f60\u53ef\u4ee5\u91c7\u7528\u5355\u4e0b\u6807\u8bbf\u95ee\u65b9\u5f0f\u3002
\u6bd4\u5982A(a)\u663e\u793a\u7684\u7ed3\u679c\u662fA\u77e9\u9635\u7684\u7b2c1,3,4\u2026\u2026\u4e2a\u5143\u7d20\uff1b
\u800cA(1,a)\u663e\u793a\u7684\u662fA(1,1),A(1,3),A(1,4)\u2026\u2026\u7684\u7ed3\u679c\u3002
Matlab\u4e2d\u6570\u7ec4\u5143\u7d20\u5f15\u7528\u6709\u4e09\u79cd\u65b9\u6cd5\uff1a
1.\u4e0b\u6807\u6cd5(subscripts)
2.\u7d22\u5f15\u6cd5(index)
3.\u5e03\u5c14\u6cd5(Boolean)
\u5728\u4f7f\u7528\u8fd9\u4e09\u79cd\u65b9\u6cd5\u4e4b\u524d\uff0c\u5927\u5bb6\u5934\u8111\u4e00\u5b9a\u8981\u6e05\u6670\u7684\u8bb0\u4f4f\uff0cMatlab\u4e2d\u6570\u7ec4\u5143\u7d20\u662f\u6309\u5217\u5b58\u50a8(\u4e0eFortran\u4e00\u6837)\uff0c\u6bd4\u5982\u8bf4\u4e0b\u9762\u7684\u4e8c\u7ef4\u6570\u7ec4
A=
8 1 6
3 5 7
4 9 2
Matlab\u7684\u5b58\u50a8\u987a\u5e8f\u662f8,3,4,1,5,9,6,7,2\uff0c\u4e5f\u5c31\u662f\u8bf4\u5148\u884c\u540e\u5217\uff0c\u5bf9\u4e8e3\u7ef4\u6570\u7ec4\u5462\uff0c\u5c31\u662f\u5148\u884c\u540e\u5217\u518d\u9875
\u5bf9\u5e94\u4e2a\u5143\u7d20\u7684\u7d22\u5f15\u548c\u4e0b\u6807\u5206\u522b\u4e3a
Element Index Subscripts
8 1 (1,1)
3 2 (2,1)
4 3 (3,1)
1 4 (1,2)
5 5 (2,2)
9 6 (3,2)
6 7 (1,3)
7 8 (2,3)
2 9 (3,3)
\u4ece\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u5df2\u7ecf\u5f88\u6e05\u6670\u7684\u8bf4\u660e\u4e86\u4e0b\u6807\u548c\u7d22\u5f15\u7684\u533a\u522b\u4e86\uff0c\u4e5f\u5c31\u662f\u8bf4Matlab\u4e3a\u6ca1\u6709\u4e2a\u5143\u7d20\u5206\u914d\u4e86\u4e00\u4e2a\u552f\u4e00\u8bc6\u522b\u7684ID(\u5373index)
1.\u4e0b\u6807\u6cd5\u5f15\u7528
A(ii,jj)\uff1a\u5176\u4e2dii\u548cjj\u53ef\u4ee5\u662f\u4e00\u7ef4\u5411\u91cf\u3001\u6807\u91cf\u3001\u201c:\u201d\u53f7\u6216\u8005\u201cend\u201d
\u5927\u5bb6\u5bf9\u4e0b\u6807\u4f30\u8ba1\u6bd4\u8f83\u719f\u6089\uff0c\u7531\u4e8e\u5728C\u8bed\u8a00\u4e2d\u63a5\u89e6\u8fc7\uff0c\u4f46\u662f\u6211\u8fd9\u91cc\u9700\u8981\u5f3a\u8c03\u7684\u662f\uff0cMatlab\u7684\u4e0b\u6807\u662f\u53ef\u4ee5\u591a\u884c\u591a\u5217\u540c\u65f6\u5f15\u7528\u7684\uff0c\u800c\u50cfC\u8bed\u8a00\u7b49\u4e00\u6b21\u53ea\u80fd\u5f15\u7528\u4e00\u4e2a\uff0c\u6bd4\u5982
A(2:3,3:-1:1)\u8868\u793a\u5f15\u7528\u6570\u7ec4\u4e2d\u76842~3\u884c\uff0c3~1\u5217\u5bf9\u5e94\u7684\u5143\u7d20
A(:,end)\u8868\u793a\u5f15\u7528\u6700\u540e\u4e00\u5217\u5143\u7d20\uff0c\u201c:\u201d\u8868\u793a\u6240\u6709\u5217\u6216\u884c\uff0c\u201cend\u201d\u8868\u793a\u6700\u540e\u4e00\u5217\u6216\u5217\uff0c\u201cend-n\u201d\u8868\u793a\u5012\u6570\u7b2cn\u884c\u6216\u5217
A(1,end-1)\u8868\u793a\u5f15\u7528\u7b2c1\u884c\u5012\u6570\u7b2c2\u4e2a\u5143\u7d20
A([2 1 3 3],[1 1 2 2 1])\u8868\u793a\u5f15\u7528\u6309\u4e24\u4e2a\u5411\u91cf\u5f15\u7528\u6307\u5b9a\u7684\u5143\u7d20\uff0c\u5373A\u4e2d\u7684\u7b2c2,1,3,3\u884c\u548c\u7b2c1,1,2,2,1\u5217\u5bf9\u5e94\u7684\u5143\u7d20
>>A=magic(3)
A =
8 1 6
3 5 7
4 9 2
>>A(2:3,3:-1:1)
ans =
7 5 3
2 9 4
>>A(:,end)
ans =
6
7
2
>>A(1,end-1)
ans =
1
>>A([2 1 3 3],[1 1 2 2 1])
ans =
3 3 5 5 3
8 8 1 1 8
4 4 9 9 4
4 4 9 9 4
2.\u7d22\u5f15\u6cd5\u5f15\u7528(\u8bf4\u767d\u4e86\u7d22\u5f15\u5c31\u662f\u5b58\u50a8\u987a\u5e8f)
A(index)\uff1aindex\u53ef\u4ee5\u662f\u4efb\u610f\u7684\u6570\u7ec4\uff0cindex\u7684\u5143\u7d20\u5fc5\u987b\u662f\u6b63\u6574\u6570\uff0c\u4e14\u4e0d\u5927\u4e8enumel(A)\uff0c\u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u5c3a\u5bf8\u4e0eindex\u4e00\u6837\u7684\u6570\u7ec4
\u4e0b\u6807\u548c\u7d22\u5f15\u4e4b\u95f4\u53ef\u4ee5\u901a\u8fc7ind2sub\u548csub2ind\u51fd\u6570\u76f8\u4e92\u8f6c\u6362\uff0c\u5177\u4f53\u53ef\u4ee5\u770b\u5e2e\u52a9\uff0c\u5f88\u7b80\u5355
[I,J] = ind2sub(siz,IND)
IND = sub2ind(siz,I,J)
\u8fd8\u6709\u4f7f\u7528A(:)\u5c31\u53ef\u4ee5\u5c06\u6570\u7ec4A\u8f6c\u6362\u4e3a\u5217\u5411\u91cf
A(8)\uff1a\u8868\u793a\u5f15\u7528A\u7684\u7b2c8\u4e2a\u5143\u7d20
B=A([1 10 5 2 2 1 3])\uff1a\u8868\u793a\u4f9d\u6b21\u5f15\u7528A\u7684\u7b2c1,10,5,2,2,1,3\u4e2a\u5143\u7d20\uff0c\u8fd4\u56de\u4e0eindex\u5c3a\u5bf8\u76f8\u540c\u7684\u6570\u7ec4\uff0c\u4e5f\u5c31\u662f\u8bf4size(B)=size(index)
A([2 5 9;1 1 1;8 5 6])\uff1a\u8fd4\u56de\u7684\u65f6\u4faf\u662f\u4e00\u4e2a3*3\u7684\u77e9\u9635
>>A=magic(5)%\u62ec\u53f7\u4e2d\u4e3a\u7d22\u5f15\u503c
A =
17 (1) 24 (6) 1 (11) 8 (16) 15 (21)
23 (2) 5 (7) 7 (12) 14 (17) 16 (22)
4 (3) 6 (8) 13 (13) 20 (18) 22 (23)
10 (4) 12 (9) 19 (14) 21 (19) 3 (24)
11 (5) 18 (10) 25 (15) 2 (20) 9 (25)
>>A(8)
ans =
6
>>A([1 10 5 2 2 1 3])
ans =
17 18 11 23 23 17 4
>>A([2 5 9;1 1 1;8 5 6])
ans =
23 11 12
17 17 17
6 11 24
3.\u5e03\u5c14\u6cd5\u5f15\u7528
A(X)\uff1aX\u662f\u4e00\u4e2a\u67090\u548c1\u7ec4\u6210\u5e03\u5c14\u578b\u6570\u636e\uff0c\u4e14size(A)=size(X)\uff0c\u5bf9\u5e94\u4f4d\u7f6e\u4e3a1\u5219\u7559\u4e0b\u8be5\u6570\u636e\uff0c0\u5219\u53bb\u6389\uff0c\u6700\u540e\u6309A\u4e2d\u7684\u5b58\u50a8\u987a\u5e8f\uff0c\u8fd4\u56de\u4e00\u4e2a\u5217\u5411\u91cf
\u5047\u5982\u8bf4A\u662f3*3\u7684\u6570\u7ec4
A(logical([1 0 0;0 1 0;0 0 1]))\uff1a\u8868\u793a\u5f15\u7528\u4e86\u6570\u7ec4A\u7684\u5bf9\u89d2\u7ebf\u5143\u7d20\uff0c\u6ce8\u610f\u5fc5\u987b\u4f7f\u7528logical\u5c060/1\u6570\u7ec4\u8f6c\u6362\u4e3a\u5e03\u5c14\u578b
>>A=magic(3)%\u751f\u6210\u4e00\u4e2a3*3\u7684\u6570\u7ec4
A=
8 1 6
3 5 7
4 9 2
>>x=logical([1 1 0;0 1 1;1 0 1])%\u5c06double\u8f6c\u5316\u4e3aboolean\u578b\u6570\u636e
x =
1 1 0
0 1 1
1 0 1
>>A(x)%\u5f15\u7528\u5bf9\u5e94\u4f4d\u7f6e\u4e3a1\u7684\u6570\u636e\uff0c\u8fd4\u56de\u5217\u5411\u91cf
ans =
8
4
1
5
7
2
>>x=A>5%\u662f\u6709\u4e86\u6bd4\u8f83\u8bed\u53e5\uff0c\u8fd4\u56de\u5e03\u5c14\u578b\u6570\u636e\uff0c\u5bf9\u5e94\u4f4d\u7f6e\u6570\u636e\u5927\u4e8e5\u7684\u4e3a1\uff0c\u5426\u5219\u4e3a0
x =
1 0 1
0 0 1
0 1 0
>>A(x)%\u8fd4\u56de\u5927\u4e8eA\u4e2d\u5927\u4e8e5\u7684\u5143\u7d20\uff0c\u5176\u5b9e\u8be5\u547d\u4ee4\u53ef\u4ee5\u4e00\u6b21\u6027\u6267\u884cA(A>5)\u6216\u8005find(A>5)\uff0c\u524d\u8005\u8fd4\u56de\u5177\u4f53\u5143\u7d20\uff0c\u540e\u8005\u8fd4\u56de\u5927\u4e8e5\u7684\u6570\u636e\u7684\u7d22\u5f15\u503c
ans =
8
9
6
7
>>A(A>5)%\u4e00\u6b21\u6027\u6267\u884c\u4e0a\u9762\u7684\u547d\u4ee4
ans =
8
9
6
7
>>indx=find(A>5)%\u67e5\u627eA\u4e2d\u5bf9\u4e8e5\u7684\u5143\u7d20\uff0c\u8fd4\u56de\u5b83\u4eec\u7684\u7d22\u5f15(index)\u503c\uff0c\u6b64\u65f6\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7A(index)\u8fd4\u56de\u5177\u4f53\u7684\u5143\u7d20
index =
1
6
7
8
\u589e\u52a0\u5185\u5bb9
1\u3001\u5411\u91cf\u7684\u521b\u5efa
1\uff09\u76f4\u63a5\u8f93\u5165\uff1a
\u884c\u5411\u91cf\uff1aa=[1,2,3,4,5]
\u5217\u5411\u91cf\uff1aa=[1;2;3;4;5]
2\uff09\u7528\u201c:\u201d\u751f\u6210\u5411\u91cf
a=J:K \u751f\u6210\u7684\u884c\u5411\u91cf\u662fa=[J,J+1,\u2026,K]
a=J:D:K \u751f\u6210\u884c\u5411\u91cfa=[J,J+D,\u2026,J+m*D],m=fix((K-J)/D)
3\uff09\u51fd\u6570linspace \u7528\u6765\u751f\u6210\u6570\u636e\u6309\u7b49\u5dee\u5f62\u5f0f\u6392\u5217\u7684\u884c\u5411\u91cf
x=linspace(X1,X2):\u5728X1\u548cX2\u95f4\u751f\u6210100\u4e2a\u7ebf\u6027\u5206\u5e03\u7684\u6570\u636e\uff0c\u76f8\u90bb\u7684\u4e24\u4e2a\u6570\u636e\u7684\u5dee\u4fdd\u6301\u4e0d\u53d8\u3002\u6784\u6210\u7b49\u5dee\u6570\u5217\u3002
x=linspace(X1,X2,n): \u5728X1\u548cX2\u95f4\u751f\u6210n\u4e2a\u7ebf\u6027\u5206\u5e03\u7684\u6570\u636e\uff0c\u76f8\u90bb\u7684\u4e24\u4e2a\u6570\u636e\u7684\u5dee\u4fdd\u6301\u4e0d\u53d8\u3002\u6784\u6210\u7b49\u5dee\u6570\u5217\u3002
4\uff09\u51fd\u6570logspace\u7528\u6765\u751f\u6210\u7b49\u6bd4\u5f62\u5f0f\u6392\u5217\u7684\u884c\u5411\u91cf
X=logspace(x1,x2) \u5728x1\u548cx2\u4e4b\u95f4\u751f\u621050\u4e2a\u5bf9\u6570\u7b49\u5206\u6570\u636e\u7684\u884c\u5411\u91cf\u3002\u6784\u6210\u7b49\u6bd4\u6570\u5217\uff0c\u6570\u5217\u7684\u7b2c\u4e00\u9879x(1)=10x1,x(50)=10x2
X=logspace(x1,x2,n) \u5728x1\u548cx2\u4e4b\u95f4\u751f\u6210n\u4e2a\u5bf9\u6570\u7b49\u5206\u6570\u636e\u7684\u884c\u5411\u91cf\u3002\u6784\u6210\u7b49\u6bd4\u6570\u5217\uff0c\u6570\u5217\u7684\u7b2c\u4e00\u9879x(1)=10x1,x(n)=10x2
\u6ce8\uff1a\u5411\u91cf\u7684\u7684\u8f6c\u7f6e\uff1ax=(0,5)\u2019
2\u3001\u77e9\u9635\u7684\u521b\u5efa
1\uff09\u76f4\u63a5\u8f93\u5165\uff1a\u5c06\u6570\u636e\u62ec\u5728[]\u4e2d\uff0c\u540c\u4e00\u884c\u7684\u5143\u7d20\u7528\u7a7a\u683c\u6216\u9017\u53f7\u9694\u5f00\uff0c\u6bcf\u4e00\u884c\u53ef\u4ee5\u7528\u56de\u8f66\u6216\u662f\u5206\u53f7\u7ed3\u675f
\u5982\uff1aa=[1,2,3;3,4,5],\u8fd0\u884c\u540e\uff1a
a =
1 2 3
3 4 5
2\uff09\u51fd\u6570eye\uff0c\u751f\u6210\u5355\u4f4d\u77e9\u9635
eye(n) :\u751f\u6210n*n\u9636\u5355\u4f4dE
eye(m,n):\u751f\u6210m*n\u7684\u77e9\u9635E\uff0c\u5bf9\u89d2\u7ebf\u5143\u7d20\u4e3a1\uff0c\u5176\u4ed6\u4e3a0
eye(size(A))\uff1a\u751f\u6210\u4e00\u4e2a\u77e9\u9635A\u5927\u5c0f\u76f8\u540c\u7684\u5355\u4f4d\u77e9\u9635
eye(m,n,classname):\u5bf9\u89d2\u7ebf\u4e0a\u751f\u6210\u7684\u5143\u7d20\u662f1\uff0c\u6570\u636e\u7c7b\u578b\u7528classname\u6307\u5b9a\u3002\u5176\u6570\u636e\u7c7b\u578b\u53ef\u4ee5\u662f\uff1aduoble\u3001single\u3001int8\u3001uint8\u3001int16\u3001uint16\u3001int32\u3001uint32 \u3002
3\uff09\u51fd\u6570ones \u7528ones\u751f\u6210\u51681\u7684\u77e9\u9635
ones(n) : \u751f\u6210n*n\u7684\u51681\u77e9\u9635
ones(m,n) : \u751f\u6210m*n\u7684\u51681\u77e9\u9635
ones(size(A)) : \u751f\u6210\u4e0e\u77e9\u9635A\u5927\u5c0f\u76f8\u540c\u7684\u51681\u77e9\u9635
ones(m,n,p,\u2026)\u751f\u6210m*n*p*\u2026.\u7684\u51681\u7684\u591a\u7ef4\u77e9\u9635
ones(m,n,\u2026,classname)\u5236\u5b9a\u6570\u636e\u7c7b\u578b\u4e3aclassname
4\uff09\u51fd\u6570zeros \u51fd\u6570zeros\u751f\u6210\u51680\u77e9\u9635
zeros(n):\u751f\u6210n*n\u7684\u51680\u77e9\u9635
zeros(m,n:)\u751f\u6210m*n\u7684\u51680\u77e9\u9635
zeros(size(A)): \u751f\u6210\u4e0e\u77e9\u9635A\u5927\u5c0f\u76f8\u540c\u7684\u51680\u77e9\u9635
zeros (m,n,p,\u2026)\u751f\u6210m*n*p*\u2026.\u7684\u51680\u7684\u591a\u7ef4\u77e9\u9635
zeros (m,n,\u2026,classname)\u6307\u5b9a\u6570\u636e\u7c7b\u578b\u4e3aclassname
5\uff09\u51fd\u6570rand \u51fd\u6570rand\u7528\u6765\u751f\u6210[0,1]\u4e4b\u95f4\u5747\u5300\u5206\u5e03\u7684\u968f\u673a\u51fd\u6570\uff0c\u5176\u8c03\u7528\u683c\u5f0f\u662f\uff1a
Y=rand:\u751f\u6210\u4e00\u4e2a\u968f\u673a\u6570
Y=rand(n):\u751f\u6210n*n\u7684\u968f\u673a\u77e9\u9635
Y=rand(m,n):\u751f\u6210m*n\u7684\u968f\u673a\u77e9\u9635
Y=rand(size(A)):\u751f\u6210\u4e0e\u77e9\u9635A\u5927\u5c0f\u76f8\u540c\u7684\u968f\u673a\u77e9\u9635
Y=rand(m,n,p,\u2026):\u751f\u6210m*n*p*\u2026\u7684\u968f\u673a\u6570\u591a\u7ef4\u6570\u7ec4
6\uff09\u51fd\u6570randn \u51fd\u6570rand\u7528\u6765\u751f\u6210\u670d\u4ece\u6b63\u6001\u5206\u5e03\u7684\u968f\u673a\u51fd\u6570\uff0c\u5176\u8c03\u7528\u683c\u5f0f\u662f\uff1a
Y=randn:\u751f\u6210\u4e00\u4e2a\u670d\u4ece\u6807\u51c6\u6b63\u6001\u5206\u5e03\u7684\u968f\u673a\u6570
Y=randn(n):\u751f\u6210n*n\u7684\u670d\u4ece\u6807\u51c6\u6b63\u6001\u5206\u5e03\u7684\u968f\u673a\u77e9\u9635
Y=randn(m,n):\u751f\u6210m*n\u7684\u670d\u4ece\u6807\u51c6\u6b63\u6001\u5206\u5e03\u7684\u968f\u673a\u77e9\u9635
Y=randn(size(A)):\u751f\u6210\u4e0e\u77e9\u9635A\u5927\u5c0f\u76f8\u540c\u7684\u670d\u4ece\u6807\u51c6\u6b63\u6001\u5206\u5e03\u7684\u968f\u673a\u77e9\u9635
Y=randn(m,n,p,\u2026):\u751f\u6210m*n*p*\u2026\u7684\u670d\u4ece\u6807\u51c6\u6b63\u6001\u5206\u5e03\u7684\u968f\u673a\u6570\u591a\u7ef4\u6570\u7ec4
3\u3001\u77e9\u9635\u5143\u7d20\u7684\u63d0\u53d6\u4e0e\u66ff\u6362
1\uff09 \u5355\u4e2a\u5143\u7d20\u7684\u63d0\u53d6
\u5982\uff1aa=[1,2,3;3,4,5],\u8fd0\u884c\u540e\uff1a
a =
1 2 3
3 4 5
\u8f93\u5165b=a(1,2)
b =
2
2\uff09 \u63d0\u53d6\u77e9\u9635\u4e2d\u67d0\u4e00\u884c\u7684\u5143\u7d20\uff0c
\u5982\uff1aa=[1,2,3;3,4,5],\u8fd0\u884c\u540e\uff1a
a =
1 2 3
3 4 5
\u8f93\u5165b=a(1,:)
b =
1 2 3
3\uff09 \u63d0\u53d6\u77e9\u9635\u4e2d\u67d0\u4e00\u5217\uff1a
\u5982\uff1aa=[1,2,3;3,4,5],\u8fd0\u884c\u540e\uff1a
a =
1 2 3
3 4 5
\u8f93\u5165b=a(:,1)
b =
1
3
4\uff09 \u63d0\u53d6\u77e9\u9635\u4e2d\u7684\u591a\u884c\u5143\u7d20
\u5982\uff1aa=[1,2,3;3,4,5],\u8fd0\u884c\u540e\uff1a
a =
1 2 3
3 4 5
\u8f93\u5165b=a([1,2],:)
b =
1 2 3
3 4 5
5\uff09 \u63d0\u53d6\u77e9\u9635\u4e2d\u7684\u591a\u5217\u5143\u7d20
\u5982\uff1aa=[1,2,3;3,4,5],\u8fd0\u884c\u540e\uff1a
a =
1 2 3
3 4 5
\u8f93\u5165b=a(:,[1,3])
b =
1 3
3 5
6\uff09 \u63d0\u53d6\u77e9\u9635\u4e2d\u591a\u884c\u591a\u5217\u4ea4\u53c9\u70b9\u4e0a\u7684\u5143\u7d20
\u5982\uff1aa=[1,2,3;3,4,5],\u8fd0\u884c\u540e\uff1a
a =
1 2 3
3 4 5
\u8f93\u5165b=a([1,2],[1,3])
b =
1 3
3 5
7\uff09 \u5355\u4e2a\u5143\u7d20\u7684\u66ff\u6362\uff1a
\u5982\uff1aa=[1,2,3;3,4,5],\u8fd0\u884c\u540e\uff1a
a =
1 2 3
3 4 5
\u8f93\u5165\uff1aa(2,3)=-1
a =
1 2 3
3 4 -1
4\u3001\u77e9\u9635\u5143\u7d20\u7684\u91cd\u6392\u548c\u590d\u5236\u6392\u5217
1\uff09 \u77e9\u9635\u5143\u7d20\u7684\u91cd\u6392
B=reshape(A,m,n):\u8fd4\u56de\u7684\u662f\u4e00\u4e2am*n\u77e9\u9635B\uff0c\u77e9\u9635B\u7684\u5143\u7d20\u5c31\u662f\u77e9\u9635A\u7684\u5143\u7d20\uff0c\u82e5\u77e9\u9635A\u7684\u5143\u7d20\u4e0d\u662fm*n\u4e2a\u5219\u63d0\u793a\u9519\u8bef\u3002
B=reshape(A,m,n,p):\u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u591a\u7ef4\u7684\u6570\u7ec4B\uff0c\u6570\u7ec4B\u4e2d\u7684\u5143\u7d20\u4e2a\u6570\u548c\u77e9\u9635A\u4e2d\u7684\u5143\u7d20\u4e2a\u6570\u76f8\u7b49
B=reshape(A,\u2026,[],\u2026):\u53ef\u4ee5\u9ed8\u8ba4\u5176\u4e2d\u7684\u4e00\u4e2a\u7ef4\u6570
B=reshape(A,siz) : \u7531\u5411\u91cfsiz\u6307\u5b9a\u6570\u7ec4B\u7684\u7ef4\u6570\uff0c\u8981\u6c42siz\u7684\u5404\u5143\u7d20\u4e4b\u79ef\u7b49\u4e8e\u77e9\u9635A\u7684\u5143\u7d20\u4e2a\u6570
2\uff09 \u77e9\u9635\u7684\u590d\u5236\u6392\u5217 \u51fd\u6570\u662frepmat
B=repmat(A,n):\u8fd4\u56deB\u662f\u4e00\u4e2an*n\u5757\u5927\u5c0f\u7684\u77e9\u9635\uff0c\u6bcf\u4e00\u5757\u77e9\u9635\u90fd\u662fA
B=repmat(A,m,n):\u8fd4\u56de\u503c\u662f\u7531m*n\u4e2a\u5757\u7ec4\u6210\u7684\u5927\u77e9\u9635\uff0c\u6bcf\u4e00\u4e2a\u5757\u90fd\u662f\u77e9\u9635A\u3002
B=repmat(A,[m,n,p,\u2026]):\u8fd4\u56de\u503cB\u662f\u4e00\u4e2a\u591a\u7ef4\u6570\u7ec4\u5f62\u5f0f\u7684\u5757\uff0c\u6bcf\u4e00\u4e2a\u5757\u90fd\u662f\u77e9\u9635A
5\u3001\u77e9\u9635\u7684\u7ffb\u8f6c\u548c\u65cb\u8f6c
1\uff09\u77e9\u9635\u7684\u5de6\u53f3\u7ffb\u8f6c \u5de6\u53f3\u7ffb\u8f6c\u51fd\u6570\u662ffliplr,\u8c03\u7528\u683c\u5f0f\uff1a
B=fliplr(A):\u5c06\u77e9\u9635A\u5de6\u53f3\u7ffb\u8f6c\u6210\u77e9\u9635B\u3002
\u8f93\u5165\uff1aA=[1,2,3;3,4,2]
A =
1 2 3
3 4 2
\u8f93\u5165\uff1aB=fliplr(A)
B =
3 2 1
2 4 3
2\uff09\u77e9\u9635\u4e0a\u4e0b\u7ffb\u8f6c \u51fd\u6570\uff1aflipud\uff0c\u8c03\u7528\u683c\u5f0f\uff1a
B=flipud(A):\u628a\u77e9\u9635A\u4e0a\u4e0b\u7ffb\u8f6c\u6210\u77e9\u9635B
3\uff09 \u591a\u7ef4\u6570\u7ec4\u7ffb\u8f6c \u51fd\u6570\uff1aflipdim\uff0c\u8c03\u7528\u683c\u5f0f\uff1a
B=flipdim(A,dim):\u628a\u77e9\u9635\u6216\u591a\u7ef4\u6570\u7ec4A\u6cbf\u6307\u5b9a\u7ef4\u6570\u7ffb\u8f6c\u6210B
4\uff09 \u77e9\u9635\u7684\u65cb\u8f6c \u51fd\u6570\uff1arot90\uff0c\u8c03\u7528\u683c\u5f0f\uff1a
B=rot90(A):\u77e9\u9635B\u662f\u77e9\u9635A\u6cbf\u9006\u65f6\u9488\u65b9\u5411\u65cb\u8f6c90\u3002\u5f97\u5230\u7684
B=rot90(A,k):\u77e9\u9635B\u662f\u77e9\u9635A\u6cbf\u9006\u65f6\u9488\u65b9\u5411\u65cb\u8f6ck*90\u3002\u5f97\u5230\u7684(\u8981\u60f3\u987a\u65f6\u9488\u65cb\u8f6c\uff0ck\u53d6-1)
6\u3001\u77e9\u9635\u7684\u751f\u6210\u4e0e\u63d0\u53d6\u51fd\u6570
1\uff09 \u5bf9\u89d2\u7ebf\u51fd\u6570 \u5bf9\u89d2\u7ebf\u51fd\u6570diag\u65e2\u53ef\u4ee5\u7528\u6765\u751f\u6210\u77e9\u9635\uff0c\u53c8\u53ef\u4ee5\u6765\u63d0\u53d6\u77e9\u9635\u7684\u5bf9\u89d2\u7ebf\u5143\u7d20\uff0c\u5176\u8c03\u7528\u683c\u5f0f\uff1a
a) A=diag(v,k):\u5f53v\u662f\u6709n\u4e2a\u5143\u7d20\u7684\u5411\u91cf\uff0c\u8fd4\u56de\u77e9\u9635A\u662f\u884c\u5217\u6570\u4e3an+|k|\u7684\u65b9\u9635\u3002\u5411\u91cfv\u7684\u5143\u7d20\u4f4d\u4e8eA\u7684\u7b2ck\u6761\u5bf9\u89d2\u7ebf\u4e0a\u3002K=0 \u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\uff0ck>0\u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\u4ee5\u4e0a\uff0ck<0\u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\u4ee5\u4e0b\u3002
b) A=diag(v):\u5c06\u5411\u91cfv\u7684\u5143\u7d20\u653e\u5728\u65b9\u9635A\u7684\u4e3b\u5bf9\u89d2\u7ebf\u4e0a\uff0c\u7b49\u540c\u4e8eA=diag(v,k)\u4e2dk=0\u7684\u60c5\u51b5\u3002
c) v=diag(A,k):\u63d0\u53d6\u77e9\u9635A\u7684\u7b2ck\u6761\u5bf9\u89d2\u7ebf\u4e0a\u7684\u5143\u7d20\u4e8e\u5217\u5411\u91cfv\u4e2d\u3002
d) v=diag(A):\u63d0\u53d6\u77e9\u9635A\u7684\u4e3b\u5bf9\u89d2\u7ebf\u5143\u7d20\u4e8ev\u4e2d\uff0c\u8fd9\u79cd\u8c03\u7528\u7b49\u540c\u4e8ev=diag(A,k)\u4e2dk=0\u7684\u60c5\u51b5\u3002
2\uff09 \u4e0b\u4e09\u89d2\u9635\u7684\u63d0\u53d6 \u7528\u51fd\u6570tril\uff0c\u8c03\u7528\u683c\u5f0f\uff1a
a) L=tril(A): \u63d0\u53d6\u77e9\u9635A\u7684\u4e0b\u4e09\u89d2\u90e8\u5206
b) L=tril(A,k):\u63d0\u53d6\u77e9\u9635A\u7684\u7b2ck\u6761\u5bf9\u89d2\u7ebf\u4ee5\u4e0b\u90e8\u5206\u3002K=0 \u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\uff0ck>0\u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\u4ee5\u4e0a\uff0ck<0\u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\u4ee5\u4e0b\u3002
3\uff09 \u4e0a\u4e09\u89d2\u9635\u7684\u63d0\u53d6 \u51fd\u6570triu\uff0c\u8c03\u7528\u683c\u5f0f\uff1a
a) U=triu(A): \u63d0\u53d6\u77e9\u9635A\u7684\u4e0a\u4e09\u89d2\u90e8\u5206\u5143\u7d20
b) U=triu(A,k): \u63d0\u53d6\u77e9\u9635A\u7684\u7b2ck\u6761\u5bf9\u89d2\u7ebf\u4ee5\u4e0a\u7684\u5143\u7d20\u3002K=0 \u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\uff0ck>0\u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\u4ee5\u4e0a\uff0ck<0\u5bf9\u5e94\u4e3b\u5bf9\u89d2\u7ebf\u4ee5\u4e0b\u3002
\u903b\u8f91\u5224\u65ad\u6d6e\u70b9\u6570\u4e00\u822c\u90fd\u6709\u8fd9\u4e2a\u95ee\u9898, \u4e0d\u80fd\u4e25\u683c\u76f8\u7b49, \u53ef\u4ee5\u7528 (x-x0)<eps \u4ee3\u66ffx==x0\u76f8\u7b49\u5224\u65ad
ind=sub2ind(size(A),X,Y);B=A(ind);
B就是 A(1,5)，A(2,6)，A(3,7)，A(4,8)组成的列向量
绛旓細浠ヤ笂浠ｇ爜涓瑽涔熷彲浠ヤ负2缁鐨锛屽畬鍏ㄤ竴鏍风殑浠ｇ爜銆備絾缁撴灉A鏄竴缁寸殑锛屽埛閫夊嚭鏉ョ殑鏈塱f鏉′欢鍐冲畾 涓婅堪浠ｇ爜鏁堢巼鍙兘涓嶄匠锛堜汉鎴朆濡傛灉涓嶆槸鍑犱釜浜垮ぇ灏忕殑鐭╅樀鏄療瑙変笉鍑烘潵鐨勶級褰卞搷鍏舵晥鐜囨槸姣忔閮借鑷姩鎵╁睍A鐭╅樀 鏀硅繘鏂规硶鏄疉=size(1,length(B));浠ｆ浛A=[];鍦ㄦ渶鍚庤A(ka:end)=[];鍘绘帀娌＄敤鐨勫熬宸达紝杩欐牱鍦...
绛旓細杩欎釜涓嶅彨鍏ㄦ帓鍒楀惂锛屽簲璇ュ彨鍏ㄧ粍鍚堛傜紪浜嗕釜鍑芥暟缁欎綘锛歠unction C = allcombs(varargin)n = nargin;if n < 2, error('Insufficient input'); ends = '[x1';for i=2:n s = [s sprintf(',x%i',i)];ends = [s ']=ndgrid(varargin{:});'];eval(s);s = '[x1(:)';for i=2...
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绛旓細MATLAB鏄竴娆惧晢涓氭暟瀛﹁蒋浠讹紝鐢ㄤ簬绠楁硶寮鍙戙佹暟鎹彲瑙嗗寲銆佹暟鎹垎鏋愪互鍙婃暟鍊艰绠楃殑楂樼骇鎶鏈绠楄瑷鍜屼氦浜掑紡鐜銆傚叾涓紝鏄疢ATLAB涓壒鏈夌殑涓绉嶆暟鎹被鍨嬨傚緢澶氱敤鎴疯繕涓嶅お浼浣跨敤MATLAB涓鐨鍏鑳鏁扮粍锛屼粖澶╋紝灏忕紪灏辨潵甯姪浣犺В鍐宠繖涓棶棰樸傚叿浣撳涓嬶細1. 棣栧厛锛屾垜浠厛鏉ョ畝鍗曚粙缁嶄竴涓嬫湁鍏冲厓鑳炴暟缁勭殑姒傚康銆俛=cell(0)锛...
绛旓細matlab涓瀹炵幇鏁扮粍缁欐暟缁勮祴鍊兼楠ゅ涓嬶細1銆侀鍏堬紝鎴戜滑鎵撳紑MATLAB缂栫▼杞欢銆傚湪鍛戒护琛屼腑杈撳叆A=[1,2,3;4,5,6;7,8,9].鍒涘缓涓涓3*3鏁扮粍鐭╅樀銆2銆侀鍏堬紝鎴戜滑瀵圭煩闃佃繘琛岃浆缃搷浣溿傝緭鍏'锛屾寜涓嬪洖杞﹀嵆鍙3銆佹澶栵紝杞疆鎴戜滑杩樺彲浠ョ敤鍛戒护鏉ュ疄鐜帮紝鍗硉ranspose(A)銆傛寜涓嬪洖杞﹀悗鍙戠幇A宸茬粡琚浆缃紝鍜岀浜屾...
绛旓細A1=A(1:100);A2=A(2:101)...鍙橀噺i=3 A3=A(i:99+i)=== 缂栫▼鏈変釜鍩烘湰姒傚康鍙惊鐜,璋佽浣犺緭鍏2901娆′簡?for/while涓涓嬩笉灏辫浜嗗悧 寰幆浣撲腑姣忔寰楀埌鍒嗗悜閲忓氨璁板綍鍒版暟缁勪腑 寰幆缁撴潫,浣鐨勬暟缁勯噷闈涓嶅氨鏄墍鏈夌殑鍒嗗悜閲忓悧??
绛旓細1銆鍦╩atlab涓绱㈠紩瓒呭嚭鏁扮粍鑼冨洿锛岄鍏堟鏌ヤ笅鏄笉鏄澶鍐欎簡涓涓暟锛岀劧鍚庡彲浠ユ鏌ヤ笅鏁扮粍鐨勪笅鏍囨槸涓嶆槸鏈夎秺鐣屻侻ATLAB鏄痬atrix&laboratory涓や釜璇嶇殑缁勫悎锛屾剰涓虹煩闃靛伐鍘傦紙鐭╅樀瀹為獙瀹わ級銆2銆佹柟娉曪細闄愬埗绱㈠紩鍙栧艰寖鍥0鍒帮紙鏁扮粍闀垮害-1锛夛紝鎴栬呭鍔犳暟缁勭殑闀垮害銆俛rr[0]=1锛沘rr[1]=2锛涙鏁扮粍闀垮害涓2锛屼笅鏍囨渶澶т负1...
绛旓細x=ones(1,n)琛ㄧずx涓哄叏0鏁扮粍锛泀=zeros(1,n)琛ㄧずq涓哄叏0鏁扮粍锛沶=length(a)琛ㄧず鑾峰緱鏁扮粍a鐨勬渶澶х淮搴︺1銆佹暟缁勭殑缁存暟锛鍦∕ATLAB涓锛屽厑璁告爣閲忔暟鎹部琛屻佸垪銆侀〉绛夋柟鍚戞帓鍒楁垚 鈥橀暱鏂逛綋鈥欙紝鑰屾瀯鎴愭暟缁勶紝鑰岃銆佸垪銆侀〉绛夋帓鍒楁柟鍚戝氨鍒嗗埆琚 绉颁负琛岀淮銆佸垪缁村拰椤电淮銆2銆佹暟缁勭殑瑙勬ā鍙婄浉鍏虫湳璇細鏁扮粍娌挎煇...
