A = [1 2;3 4; 5 6] A = 1 2 3 4 5 6
size()返回矩阵的大小
size(A) ans = 3 2
返回A的行数
size(A,1) ans = 3
返回A的列数
size(A,2) ans = 2
返回v的最大维数
>> v = [1 2 3 4] v = 1 2 3 4 >> length(v) ans = 4
返回A的最大维数（A 3*2）
>> length(A) ans = 3
文件处理
octave的安装路径
>> pwd ans = G:octaveoctave-5.1.0-w64
ls显示当前目录下的文件结构
>> ls Volume in drive G is 新新加加卷卷 Volume Serial Number is E45B-C624 Directory of G:octaveoctave-5.1.0-w64 [.] [etc] msys2.ico post-install.bat [..] fc_update.bat msys2_shell.cmd README.html [clang32] HG-ID [notepad ] [tmp] [clang64] [home] octave-firsttime.vbs [usr] cmdshell.bat [mingw32] octave.vbs [var] [dev] [mingw64] [opt] 9 File(s) 40,592 bytes 14 Dir(s) 239,150,755,840 bytes free
cd进入路径
>> cd ‘C:Users22735Desktopos‘ >> pwd ans = C:Users22735Desktopos >> ls Volume in drive C has no label. Volume Serial Number is A4A1-9EDE Directory of C:Users22735Desktopos [.] [..] 0 File(s) 0 bytes 2 Dir(s) 67,279,585,280 bytes free
加载数据
load featureX.dat load(‘featureX.dat‘)
who显示定义的所有变量
>> who Variables in the current scope: A I a ans c sz v w
whos显示更详细的信息
>> whos Variables in the current scope: Attr Name Size Bytes Class ==== ==== ==== ===== ===== A 3x2 48 double I 4x4 32 double a 1x1 8 double ans 1x25 25 char c 3x4 96 double sz 1x2 16 double v 1x4 32 double w 1x10000 80000 double Total is 10066 elements using 80257 bytes
clear删除变量
>> clear I >> who % I已经不见了 Variables in the current scope: A a ans c sz v w
将priceY的前10个数据赋值给v
>> v = priceY(1:10) v = 0.134924 0.065742 0.863374 0.139802 0.677121 0.654762 0.141145 0.228309 0.789854 0.451826
将数据存储在硬盘里
>> save hello.txt v;
>> save hello.txt v -ascii; % save as text(ASCII)ASCII格式
clear 删除所有的变量
>>clear
A(m,n)获取矩阵中特定的值
>> A A = 1 2 3 4 5 6
>> A(3,2)
ans = 6
A(m,:)获取第m行的数据
>> A(2,:) ans = 3 4
A(:,n)获取第n列的数据
>> A(:,1) ans = 1 3 5
：冒号代表该行或者该列所有的数据
显示A矩阵第1行和第3行的数据
>> A([1 3], :) ans = 1 2 5 6
按行列替换元素
>> A(:,2) = [10;11;12] A = 1 10 3 11 5 12
添加列向量B = [A , [column vector]]
>> A = [A,[100; 101; 102]] A = 1 10 100 3 11 101 5 12 102
将A作为列向量显示
>> A(:) ans = 1 3 5 10 11 12 100 101 102
结合两个矩阵C = [A B]
>> B = [A,A] B = 1 10 100 1 10 100 3 11 101 3 11 101 5 12 102 5 12 102
竖放置C = [A ; B]
>> B = [A;A] B = 1 10 100 3 11 101 5 12 102 1 10 100 3 11 101 5 12 102