Octave cheatset

File opening

clear all;
clf;

File operations

To include a *.m file (like test.m) at the location in the file simply use the filename without *.m in the code. E.g. to include “test.m” simply put “test” into the code.

Matrices & Vectors

m x n = column x row = Zeile x Spalte

a = [1;2;3] # vector 3×1 (vertical)
b = [1,2,3] # 1×3 (horizontal)

a = [1;2;3] # vector 3×1 (vertical)
b = [1,2,3] # 1×3 (horizontal)

c = [
1,2,3,4;
1,8,5,7;
1,8,6,8;
];

r3 = c(:3); # select 3rd row

Filter, find and concanate

b = find( c(:2)==8 ) # return all values from 2nd row of c where value is 8

C = [A,B] # horizontal_concanation
C = [A;B] # vertical concanation

for concanation can use:

horzcat (array1, array2, …, arrayN)
vertcat (array1, array2, …, arrayN)

Plotting

fig1 = figure(1);
hold on;
title (“Titel”);
xlabel (“x-axis”);
ylabel (“y-axis”);
grid on;
grid minor on;
box on;

plot(x, y, “+”, “markersize”, 10, ‘color’, ‘red’); # markers only
# to add line connecting markers -> use linestyle

legend(‘S11′,’S22’, “location”, “southeast”)
hold off;

Vertical & Horizontal lines

plot([x,x],[0,8], “linestyle”, “–“); # vertical line at x
plot([0,8],[y,y], “linestyle”, “–“); # horizontal line a y

Plot to pdf export

print (fig1, “my_pdfname.pdf”, “-dpdflatexstandalone”);
system (“pdflatex my_pdfname”);
open my_pdfname.pdf

Strings

str_result = strcat(str1, str2);
str = num2str(my_number)

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