problem with an if statement
Show older comments
Dear all,
I have A =[
1 2 0 2 11 0;
2 3 0 30 11 -2;
3 4 0 28 12 -6;
4 5 0 25 1 -9;
5 6 0 22 2 -6;
6 7 0 22 3 -12;
7 8 0 19 4 -13;
8 9 0 17 5 -17;
9 10 0 14 6 -18;
10 11 0 12 7 -22;
11 12 0 9 8 -25;
12 13 0 6 9 -26;
13 14 0 4 10 -30;
14 15 0 1 11 -1;
15 16 0 29 11 -3;
16 17 0 27 12 0;
17 18 0 31 1 -3;
18 19 0 28 2 0;
19 20 0 28 3 -6;
20 21 0 25 4 -7;
21 22 0 23 5 -11;
22 23 0 20 6 -12;
23 24 0 18 7 -16;
24 25 0 15 8 -19;
25 26 0 12 9 -20;
26 27 0 10 10 -24;
27 28 0 7 11 -25;
28 29 0 5 12 -29;
29 30 0 2 1 -1;
30 31 0 30 1 -4;
31 32 0 27 2 -1;
32 33 0 27 3 -7;
33 34 0 24 4 -8;
34 35 0 22 5 -12;
35 36 0 19 6 -13;
36 37 0 17 7 -17;
37 38 0 14 8 -20;
38 39 0 11 9 -21;
39 39 0 9 10 -2]
I want to apply the following if statement: if the fourth column is 1 or 2 AND the fifth column contains identical successive numbers AND the element in the laste column in not zero then replace every other corresponding element in the third column with the corresponding element (in absolute value) from the last column
The if statement should select the following elements
B=[
14 15 0 1 11 -1;
15 16 0 29 11 -3;
29 30 0 2 1 -1;
30 31 0 30 1 -4;]
and then the action is to obtain
B=[
14 15 1 1 11 -1;
15 16 0 29 11 -3;
29 30 1 2 1 -1;
30 31 0 30 1 -4;]
So the new A should be
Anew =[
1 2 0 2 11 0;
2 3 0 30 11 -2;
3 4 0 28 12 -6;
4 5 0 25 1 -9;
5 6 0 22 2 -6;
6 7 0 22 3 -12;
7 8 0 19 4 -13;
8 9 0 17 5 -17;
9 10 0 14 6 -18;
10 11 0 12 7 -22;
11 12 0 9 8 -25;
12 13 0 6 9 -26;
13 14 0 4 10 -30;
14 15 1 1 11 -1;
15 16 0 29 11 -3;
16 17 0 27 12 0;
17 18 0 31 1 -3;
18 19 0 28 2 0;
19 20 0 28 3 -6;
20 21 0 25 4 -7;
21 22 0 23 5 -11;
22 23 0 20 6 -12;
23 24 0 18 7 -16;
24 25 0 15 8 -19;
25 26 0 12 9 -20;
26 27 0 10 10 -24;
27 28 0 7 11 -25;
28 29 0 5 12 -29;
29 30 1 2 1 -1;
30 31 0 30 1 -4;
31 32 0 27 2 -1;
32 33 0 27 3 -7;
33 34 0 24 4 -8;
34 35 0 22 5 -12;
35 36 0 19 6 -13;
36 37 0 17 7 -17;
37 38 0 14 8 -20;
38 39 0 11 9 -21;
39 39 0 9 10 -2]
Is there a clever coding for this?
1 Comment
Conrad
on 1 Aug 2012
If you look at your B matrix
B=[
14 15 0 1 11 -1;
15 16 0 29 11 -3;
29 30 0 2 1 -1;
30 31 0 30 1 -4;]
the rows
[15 16 0 29 11 -3]
and
[30 31 0 30 1 -4]
do not have a 1 or 2 in the fourth column, so how where they selected? According to the logic given, it does not make sense.
Accepted Answer
Okay, think I know what you mean... this should do it.
c5 = [A(2:end,5); NaN];
idx = ((A(:,4)==1)|(A(:,4)==2))&(A(:,5)==c5)&(A(:,6)~=0);
B = A(idx,:);
A(idx,3) = abs(A(idx,6));
Tested with your example and gives the correct value for A.
More Answers (0)
Categories
Find more on Logical in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
