Matlab基础语法

Matlab基础语法

1. 文件以字母开头
2. % 注释
3. help+函数名 帮助文档
4. 语句后面不加分号直接在输结果
5. clc 清屏

x = 5

    x =

     5

x = [1 2 3] %行向量

    x =

     1     2     3

x = [1,2,3] %行向量

    x =

     1     2     3

x = [1;2;3] %列向量

    x =

     1
     2
     3

x = [1 2 3

4 5 6] %手动换行

    x =

     1     2     3
     4     5     6

x = [1 2 3;4 5 6;7 8 9] %自动换行

    x =

     1     2     3
     4     5     6
     7     8     9

x = [0:2] %x等于0-2，步长默认为1

x =

     0     1     2

x = [0:2]’ %同上，转置

x =

     0
     1
     2

x = [0:0.5:2] %同上，步长为0.5

x =

    0    0.5000    1.0000   1.5000    2.0000

x = linspace(0,2,5) %0-2,分成五等份

x =

     0    0.5000    1.0000    1.5000    2.0000

x = zeros(2,3) %二行三列0向量

x =

     0     0     0
     0     0     0

y = ones(2) %2阶全1阵

y =

     1     1
     1     1

x = eye(2) %2阶单位阵

x =

     1     0
     0     1

pi %π

ans =

    3.1416

i %默认为复数

ans =

   0.0000 + 1.0000i

j %同上

ans =

   0.0000 + 1.0000i

x = 1/0 %无穷大

x =

   Inf

0/0 %空

ans =

   NaN

C = A * B %矩阵叉乘

C =

    30    37    44
    66    85   104
   102   133   164

C = A.* B %矩阵点乘

C =

     1     6    15
    16    25    36
    49    64    81

I = A^2 %相当于A*A

I =

    30    36    42
    66    81    96
   102   126   150

J = A.^2 %相当于A.*A

J =

     1     4     9
    16    25    36
    49    64    81

A(1,3) %第一行第三列

ans =

     3

A(2) %列排序，第二个值

ans =

     4

A(2,:) %第二行，全部元素

ans =

     4     5     6

A(1:2,1:3) %1至2行，1至3列

ans =

     1     2     3
     4     5     6

A==B %每个元素逐个比较，相同为1，不同为0

ans =

     1     0     0
     1     1     1
     1     1     1

A>3&B<5 %A中元素大于3且B中元素小于5

ans =

     0     0     0
     1     0     0
     0     0     0

A>3|B<5

ans =

     1     1     0
     1     1     1
     1     1     1

xor(A>3,B<7) %异或

ans =

     1     1     1
     0     0     0
     1     1     1

A(A<0) = 0

A =

     1     2     3
     4     5     6
     7     8     9

A<3

ans =

     1     1     0
     0     0     0
     0     0     0

B(B(:,1)<2,:) = 0

B =

     0     0     0
     4     5     6
     7     8     9

C = flipud(A) %上下颠倒

C =

     7     8     9
     4     5     6
     1     2     3

C = rot90(A) %旋转90度

C =

     3     6     9
     2     5     8
     1     4     7

sum(A) %列相加,相当于sum(A,1)

ans =

    12    15    18

sum(A,2) %行相加

ans =

     6
    15
    24

sum(A,1)

ans =

    12    15    18

sum(sum(A))

ans =

    45

max(A) %每列最大值

ans =

     7     8     9

max(A,[],1)

ans =

     7     8     9

max(A,[],2)

ans =

     3
     6
     9

max(A,2) % a>2?a:2

ans =

     2     2     3
     4     5     6
     7     8     9

x = 0:pi/6:pi %0到π等分6份

x =

         0    0.5236    1.0472    1.5708    2.0944    2.6180    3.1416

y = sin(x)

y =

         0    0.5000    0.8660    1.0000    0.8660    0.5000    0.0000

z = asin(y)

z =

         0    0.5236    1.0472    1.5708    1.0472    0.5236    0.0000

abs(x) %绝对值

ans =

         0    0.5236    1.0472    1.5708    2.0944    2.6180    3.1416

sqrt(x)

ans =

         0    0.7236    1.0233    1.2533    1.4472    1.6180    1.7725

ceil(x) %ceiling

ans =

     0     1     2     2     3     3     4

fix(x) %靠近0取整

ans =

     0     0     1     1     2     2     3

floor(x) %向下取整

ans =

     0     0     1     1     2     2     3

round(x) %四舍五入

ans =

     0     1     1     2     2     3     3