Matlab Array

All MATLAB variables are arrays. So, each numeric variable can contain multiple numbers. You can store related data in one variable by using an array. 所有的变量都是数组

Because arrays are a basic programming tool in the MATLAB language, it’s important to get to know them and the terminology used to describe them.

标量 scalar

In MATLAB, a single number, called a scalar, is represented by a 1-by-1 array, meaning the array contains one row and one column.

向量 vector

1. 直接列写

When you separate numbers by using spaces , MATLAB combines the numbers into a row vector, which is an array with one row and multiple columns (1-by-n).

When you separate numbers by using semicolons, MATLAB creates a column vector (n-by-1).

2. ：运算符

y=Start : Spaceing : End

知道步长 For long vectors, entering individual numbers is not practical. An alternative, shorthand method for creating evenly spaced vectors is to use the colon operator (:) and specify only the start and end values. the : operator uses a default spacing of 1. However, you can specify a different spacing.

3. linspace

y=linspace(first,last,number_of_elements) 知道数字的个数 If you know the number of elements you want in a vector (instead of the spacing between each element), you can use the linspace function.
Note the use of commas (,) to separate inputs to the linspace function.

向量转置

Transpose x from a row vector to a column vector using the transpose operator '.

注意

Both linspace and the : operator create row vectors. 都产生行向量 如果要生成列向量，可以转置 x=x'

x=[3 5]  
x=[3;5]
 
y=20 : 2 :26   determine the size of an existing matrix
rand(size(x))   x=2
y=data(:,2)  %% 提取所有行的第二列
 
 

特殊关键字 end 行或列的最后一个索引

use only one index with a matrix, MATLAB traverses down each column in order. 如果对一个矩阵只给一个参数进行索引，则从左到右遍历列