MATLAB study notes (a) Basic Operation

Screenshot PPT document from Guo Yanfu teacher and video courseware B station

Basic Operations

1. +, -, *, /, ^. ln the operating system is a log. log (2) to the base 2. e: When e is the exponent exp ()

2. sin (cos (pi)): calculating step; ans = con (pi), sin (ans)

3. Variable variable: do not declare variables (unlike C). From left to right assignment.
   Keywords can not be when the variable: inf is infinite;
   eps is a very small number;
   NaN: Number The not A;
   i, where J is the plural use;
   PI
   with iskeyword know which keyword

4. clear in the workplace can eliminate the variable, you need to remember that behind the increase in variable eliminated, otherwise it will eliminate all
   CLC: clear the Command Run the display window
   the WHO: the Variables in at The workplace
   whos: variable of Information at The workpalce

5. FORMAT Format
   Short
   Long
   Shorte: E is in scientific notation, where numeral 10 denotes the power
   Longe
   Bank: 2 decimal places
   hex: 16 hex
   rat: the value converted into rational
   
   

6. Semicolon ";" effect: does not display the calculation result
   

ARRAY ( Vector and Marix )

Enter the Matrix and vector

The matrix a = [1 2; 3 4]: Wrap semicolon ";", the trailing column assignment is to be usedBlankYou can also use

comma","

array indexing

1
.
.

2.

Replacing Entries

删除行，同理可以删除列

Colon Operator

j:k ——>[j,j+1,j+2,…,j+m]
j:k:i ------>[j,j+k,j+2k,…j+m*k] 和fortran的区别一下，fortran的等差是i

Array Concatenation

Array Manipulation矩阵的四维运算

点乘==.*==：相对应项相乘
除/：乘逆矩阵
’ ：转置矩阵
A^2和A.*2不一样

Some Special Matrix

2是表示单位矩阵的维数，diag是对角线矩阵

max:输出矩阵中每一列最大的元素
max（max（A））：输出最大的元素
min同理
sum：每一列的和
mean：每一列的平均值
sort：排序，每列元素按小到大排序
sortrow：行排序，把最小的行放到第一行
size：输出矩阵的维数
length：输出行数
find：找矩阵中某一元素的位置。如find（A==0）

APPLICATION OF MATLAB（IF，while,do,函数…)

Script Editor

• 储存成.m

• 运行代码
  `for i=1:10
  x=linspace(0,10,101);
  plot(x,sin(x+i));
  print(gcf,’-deps’,strcat(‘plot’,num2str(1),’.ps’));

  end`
  点击运行或者F5，储存后即可得到答案。

• 记不清楚函数名可以点击上界面的FX

• 注解%，
  %%：section，分区块

• break point：debug时用，

控制语句

rem(a,b)：a除以b的余数

• 

• 

• 

• 

写另一个程序的时候记得清楚之前的数据
计算之前pro-allocating可以节省时间

tips：
2. clear
3. clc
4. ;
5. …
6. ctrl+c

Function

USER DEFINE FUNCTIONS

1. 
2. 

MATLAB IN ENGINEERING

变量

1. 变量转换
   
2. CHARACTER
   s1=‘h’
   s2=‘happy’
   s3=[s1 s2] —— hhappy
   s4=[s1;s1] —— 必须是字符数相同的
   uint16(s1)显示s1的ascii码值
   
   比较字符串 strcmp(s1,s2) 相同返回1，不同返回0
   把一个字符串逆输出
   
   
   
3. STRUCTURE
   
   
   输出单个元素
   
   

fieldnames: the structure inside the name caught out
rmfield: The refield (student, 'id') is the structure where id deleted

converts an array of structures to struct2cell cellular array, the cellular arrays to structural array ( or cell2struct structure called a vector) of.
getfield: Gets the value of a field, or fields in columns
isfield: determining whether the input is a member of an array of structures ...
call format: f = isfield (s, ' fieldname') comprises checking whether the specified structure by the S domain fieldname, if included, Back logic 1; fieldname If no domain structure or S type is not, returns to logic 0.

isstruct: used to determine, whether the input is an array of structures. Format tf = isstruct (A) if A is an array of structures, the tf = 1, otherwise, tf = 0;

Structure can be nested

4. ARRAY the CELL
   the Cell announcement

Two kinds of methods are declared using

Read cell array

num2cell() and mat2cell()

Multidimensional array
row, column, layer (layer)
CAT (concatenation): connecting

reshape the shape change matrix

chestnut

Check if something is. .

DATA ACCESS

1. FILE ACCESS
   
   save（）and load（）

Paint Elementary