Hi,
I think you can do it like this:
First, get a descriptive summary on the ‘time’ column, get a array (called "List1" for example)like:
time times
0.0 3
0.1 1
0.2 3
0.3 2
0.4 3
0.5 1
0.6 3
....
Let's call it List1. This should be easily achievable with a 'hist' command and a 'summary' command:
histime = hist(time)
summary(histime)
after this, you should be able to use the data in histime to construct the List1.
Then, use logical indexing, you should be able to get a short list of time which have occurrence times larger or equal to 3, such as :
time
0.0
0.2
0.4
0.6
.... and let's call it List2.
Last, using logical indexing again, with a loop, you should be able to extract from the original matrix the rows that have time value included in your List2.
Hope this is helpful.