## Meaning of : in the parentheses

Hi guys, I am currently doing a Matlab program for partial pivoting. I looked at my friend's example:

Code:
% Partial Pivoting
for i=1:n-1
for j = i+1:n
if (a(j,i)) > (a(i,i))
u=a(i,:);
a(i,:)=a(j,:);
a(j,:)=u;
v=b(i,1);
b(i,1)=b(j,1);
b(j,1)=v;
end
end
end
I was wondering what's the meaning of the : in the parentheses. Is it some sort of Matlab keyword? Thanks for helping
 Recognitions: Homework Help The colon stands for a whole line in the matrix. Observe: Code: octave:117> m=magic(4) m = 16 2 3 13 5 11 10 8 9 7 6 12 4 14 15 1 octave:118> m(2,:) ans = 5 11 10 8 octave:119> m(:,2) ans = 2 11 7 14 ... see? ... so m(2,:) says to take the entire second row while the m(:,2) says take the second column. http://volga.eng.yale.edu/sohrab/mat...colon_operator (Matlab works the same way...)
 Thanks bro.

Recognitions:
Homework Help

## Meaning of : in the parentheses

No worries ;)
Generally, you can try out the confusing operations you see on some random matrix and see what happens ... the magic-square function is very useful for this.