Getting Started with Matlab (file reading and writing)

First, Save,load

>> a=[1 2 3 4];>> b=[4 5 6 7]b=4     5     6     7>> Save ('B.mat','a','b');%a file named B.mat would exit>>Clear>>Load B.mat>>%load The data A and B

Second, TXT file

Suppose there is a TXT file data.txt in the current directory, the following:

1 2 3
4 5 6
7 8 9

Using the statement: Load Data.txt, the current will be more than a variable, the name is data, the content is the above text content, is a matrix

Third, the format of reading and writing

The functions involved: fopen,fscanf,fprintf,fclose;

Fid=fopen ('Data.txt','R'); a=FSCANF (FID,'%d%d%d',3);%read fromFid,the Number of elements is 3b=FSCANF (FID,'%d%d%d',3);%the rule of the middleparams  isThe same asC Languagec=FSCANF (FID,'%d%d%d',3); fclose (FID); Abcdisplay ('After write'); FID=fopen ('Data','W'); fprintf (FID,'%d%d%d\n', c); fprintf (FID,'%d%d%d\n', b); fprintf (FID,'%d%d%d\n', a); fclose (FID);

The results of the program run:

A =

1
2
3

b =

4
5
6

c =

7
8
9

After write

In the current directory will generate a file name is data, double-click to see what is inside:

7 8 9
4 5 6
1 2 3

Iv. string reading and writing

The function sscanf,sprintf is involved.

scanf reading data from a string:

>> a= ' 1 2 3 4 5 6 ';

>> b=sscanf (A, '%d ', 3);

>> b

b =

1
2
3

sprintf writes the contents to the string:

>> a=[1 2 3 4];

>> str=sprintf (' This is a string contain:%d%d%d%d ', a)

str =

This is a string contain:1234

string concatenation: strcat:

>> a= ' 1 2 3 '

A =

1 2 3

>> b= ' 4 5 6 '

b =

4 5 6

>> strcat (A, B)

Ans =

1 2 34) 5 6

The number is converted to a string: Num2str (in the same vein, string conversions are used for numeric functions (Str2Num functions)):

>> a=10

A =

10

>> b= ' num is ';
>> strcat (B,num2str (a))

Ans =

Num IS10

Getting Started with Matlab (file reading and writing)