SUNY-New Paltz Computer Simulation Lab Electrical and Computer Engineering Department SUNY – New Paltz “Lecture 11”

SUNY-New Paltz Importing and exporting data Objectives the load and save commands; low-level file I/O functions.

SUNY-New Paltz Save Command SAVE Save workspace variables to disk SAVE FILENAME saves all variables to binary “filename.mat" SAVE FILENAME X Y Z saves X, Y, and Z SAVE... -ASCII

SUNY-New Paltz Examples A =[1 2 3 ; 4 5 6] save myData A View myData.mat with a text editor save myData -ascii

SUNY-New Paltz Load Command load myData load myData.txt A=load(‘myData.txt’)

SUNY-New Paltz Low-level file I/O functions

SUNY-New Paltz Low-level file I/O functions fid = fopen(’marks.bin’, ’w’) fwrite(fid, name) fclose(fid) fread(fid, 78, ’float’); File Handle

SUNY-New Paltz Low-level file I/O functions fid = fopen(’marks.bin’, ’w’) fwrite(fid, name) Open for Write Variable Name Pointer Update

SUNY-New Paltz Low-level file I/O functions fid = fopen(’marks.bin’, ’r’) A=fread(fid, 16, ‘float’) Open for Read Variable Size&Type Pointer Update Variable Name

SUNY-New Paltz Examples 1- Create a binary file named “odd.bin” that contains all the odd numbers between 1 and 99. Examine the file by text editor. 2- Open the binary file and read its contents into an array named OddNums. 3- Append the even numbers between 2 and 100 to the above file. Examine the file by text editor.

SUNY-New Paltz MATLAB Code fid=fopen('test1.bin','w') x=[1:2:100]; fwrite(fid,x) fclose(fid); fid=fopen('test1.bin','r') y = fread(fid) fclose(fid); fid=fopen('test1.bin','a') x=[2:2:100]; fwrite(fid,x) fclose(fid); fid=fopen('test1.bin','r') y = fread(fid) fclose(fid);

SUNY-New Paltz Example Create a text file named ‘ASCII.TXT’ that contains all the ASCII characters between 0 and 255. Use a text editor to examine the file. fid=fopen('ASCII.TXT','w') x=[1:255]; fwrite(fid,char(x)) fclose(fid);