Trimming rows based on values in one column

Hello,

Suppose I have two columns in a matrix that look like this:

5   0
5   0 
5   1
5   1
5   1
6   1
7   0
8   0
9   0
9   0
1   1 
3   1 
2   1
4   1
44  1
5   0
4   1
3   1
6   0

I'd like to isolate the regions that are bounded by 0s. My second column is a switch (0 off and 1 being on). And I'd only like to look at the data where the switch is on. However, I can't just delete all rows with 0 in them because I need to know the start time and end time of each instance of the switch being on. Thus, I need a zero to be at the beginning and end of each instance. Another column in this matrix is the time stamp which I will be using in another step.

Would appreciate any help or being pointed in the right direction.

Thanks in advance.

[dpb]

Use diff() on the second column to find the +/-1 locations. I'll leave you to imagine what that tells you... :)

Answer 1

[Azzi Abdelmalek]

A=[5   0
5   0 
5   1
5   1
5   1
6   1
7   0
8   0
9   0
9   0
1   1 
3   1 
2   1
4   1
44  1
5   0
4   1
3   1
6   0]
c2=A(:,2)'
idx1=strfind(c2,[0 1])
idx2=strfind(c2,[1 0])