Azzera filtri
Azzera filtri

Nested loop problem !

1 visualizzazione (ultimi 30 giorni)
Susan
Susan il 26 Lug 2011
Hey every1.. I am working on arrays and I am finding it quite confusing and slowly getting it.. I want to replace the content of a double array with another double array and I belive since is double I should use a nested loop but I am not sure how it works?? I tried several of ways which is below but the content is not being replaced.. I keep checking it from the matlab work space .. My code is below.. the size is 2x100 and in matlab workspace is two rows.. with my code instead of replacing the content it adds extra row to array b?? I want to start the replace from a(3,1) with b(1,1). a(4,1) with b(2,1) etc then when it finishes this row the second row etc
a(x;y)
b(s,f)
d = 2;
for i=3,j=1:100
a(i,j) = b(i -d,j);
i = i+1;
j = j+1
end
Thanks in advance !!
  1 Commento
Nathan Greco
Nathan Greco il 27 Lug 2011
Note that if your arrays are size 2x100, then you should be indexing them as "a(1,3) with b(1,1). a(1,4) with b(1,2)". (How can you reach a(4,1) if there are only two rows in a? (Note that indexing goes a(row,column))

Accedi per commentare.

Risposta accettata

Nathan Greco
Nathan Greco il 26 Lug 2011
Will this do what you are looking for:
EDIT:
a(:,3:end) = b(:,1:end-2);
OR, if you really wanted a for loop:
d = 2;
for i=1:100-d
a(:,i+2) = b(:,i);
end
-Nathan
  7 Commenti
Nathan Greco
Nathan Greco il 27 Lug 2011
Based on "test" data that I am using that just use the dimensions you provided (2x100), my method seems to work. I used a = ones(2,100); and b = rand(2,100);
The result from a(:,3:end) = b(:,1:end-2); (this line alone, no for loop involved) turns a into a 2x100 (same size) array, with a(1:2,1:2) remaining ones, and the rest of a having been replaced with b.
Susan
Susan il 27 Lug 2011
Yeah, It worked perfectly fine.. was looking at the columns but read your comment that it starts with rows.. Thanks alot for your help.. Now I can carry on and learning more about the loops and arrays :)

Accedi per commentare.

Più risposte (1)

Andrei Bobrov
Andrei Bobrov il 27 Lug 2011
eg:
a = randi(15,4,10) % array 4x10
b = randi(20,2,10) %array 2x10
a(3:end,:)=b
  8 Commenti
Susan
Susan il 27 Lug 2011
Yeah thats exactly what I would like to do!!
Nathan Greco
Nathan Greco il 27 Lug 2011
And, sorry for mixing up terminology, the "rows" should actually be "columns".

Accedi per commentare.

Categorie

Scopri di più su Loops and Conditional Statements in Help Center e File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by