Store and Load All Variables
save
|
A = pi; b = [4 3 77 4 2 9 0]; test = 'sample text'; whos save testVariables.mat clear all whos |
load
|
whos ls *.mat load testVariables.mat whos A b test |
delete
|
whos ls *.mat delete testVariables.mat ls *.mat |
Store and Load Specific Variables
save
|
A = pi; b = [4 3 77 4 2 9 0]; test = 'sample text'; whos save testVariables.mat A test clear all whos |
load
|
ls *.mat load testVariables.mat whos A b test |
append
|
b = [4 3 77 4 2 9 0]; save testVariables.mat b -append whos A b test |
Files
fopen/fclose
|
fileID = fopen('testFile.m'); tline = fgetl(fileID); fclose(fileID) |
|
fid = fopen('fgetl.m'); tline = fgetl(fid); while ischar(tline) disp(tline) tline = fgetl(fid); end fclose(fid); |
permissions
|
fopen('filename','permission') 'r' - read (default) 'r+' - read and write 'w' - write/overwrite 'w+' - read and overwrite 'a' - write to end of file (append) 'a+' - read and write to end of file |
|
fileID = fopen('testFile.m','w'); tline = fgetl(fileID); fclose(fileID) tline |
Write Files
fwrite
|
fileID = fopen('nine.bin','w'); fwrite(fileID,[1:9]); fclose(fileID); |
Read Files
fread
|
fileID = fopen('nine.bin'); A = fread(fileID) |
Write Spreadsheets
xlswrite
|
filename = 'testdata.xlsx'; A = [12.7 5.02 -98 63.9 0 -.2 56]; xlswrite(filename,A) |
|
filename = 'testdata.xlsx'; A = {'Time','Temperature'; 12,98; 13,99; 14,97}; sheet = 2; xlRange = 'E1'; xlswrite(filename,A,sheet,xlRange) |
Read Spreadsheets
xlsread
|
values = {1, 2, 3 ; 4, 5, 'x' ; 7, 8, 9}; headers = {'First','Second','Third'}; xlswrite('myExample.xlsx',[headers; values]); filename = 'myExample.xlsx'; A = xlsread(filename) |
Read Range of Cells
|
filename = 'myExample.xlsx'; sheet = 1; xlRange = 'B2:C3'; subsetA = xlsread(filename,sheet,xlRange) |
Read Column
|
filename = 'myExample.xlsx'; columnB = xlsread(filename,'B:B') |
is..true or false
| isvector() | isscalar() |
| isstring() | isnumeric() |
| islogical() | isfloat() |
| isletter() | ismatrix() |
| isdatetime() | ischar() |
| isempty() | isundefined() |
Image Processing
What is an image?
Get image - imread()
|
A = imread('ngc6543a.jpg'); image(A) A(1,1,:) A(1,1) = 10; A(1,1,:) A(1,1,:) = 255 image(A) |
Save image - imwrite()
|
A = rand(500); imwrite(A,'myGray.png') 
|
|
load clown.mat imwrite(X,map,'myclown.png') 
|
|
load clown.mat newmap = copper(81); imwrite(X,newmap,'copperclown.png'); 
|
Display image - image()
|
C = [0 2 4 6; 8 10 12 14; 16 18 20 22]; image(C) colorbar 
|
|
A = imread('ngc6543a.jpg'); image(A) 
A(250:350,250:350) = 0; image(A) 
|
Audio Processing
audiowrite
|
load handel.mat filename = 'handel.wav'; audiowrite(filename,y,Fs); clear y Fs |
audioread
|
[y,Fs] = audioread('handel.wav'); |
file format
|
mp3 m4a mp4 ogg wav |
sound
|
sound(y,Fs); soundsc(y,Fs); |
mp3
|
[y,Fs] = audioread('NeverGonnaGiveYouUp.mp3'); sound(y,Fs); |
Determine Number of Input Arguments
nargin
|
function c = addme(a,b) switch nargin case 2 c = a + b; case 1 c = a + a; otherwise c = 0; end |
Determine Number of Output Arguments
nargout
|
function [dif,absdif] = subtract(y,x) dif = y - x; if nargout > 1 disp('Calculating absolute value') absdif = abs(dif); end |
Algorism and Bushism of the Day
 |
 |
|
"I just want you to know that, when we talk about war, we're really talking about peace." |
"A zebra does not change its spots." |
Lesson of the Day
How do you know anything?
It isn't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.
When something is free, you are the product being sold
Word of the day
Tom's
Diner