Identify first instance of something in a .dat file

I have a data file where one tab contains the picture that was presented on the screen another tab has the timestamp. Below is a really short version of what it looks like.

Dog   1ms
Dog   2ms
Dog   3ms
Cat   4ms
Cat   5ms
Cat   6ms
Dog   7ms
Dog   8ms
Dog   9ms
Cat   10ms
Cat   11ms
Cat   12ms

I need to get the rows with the first instance in the grouping (?) of that picture with the timestamp. Below is what I want to have:

Dog 1ms
Cat 4ms
Dog 7ms
Cat 10ms

I'm not sure how to go about doing this; any help would be appreciated!

Answer 1

[TastyPastry]

fid = fopen('test.txt');

data = textscan(fid,'%s %s');

data = [data{1} data{2}];

out = data(1,:);

for i=2:numel(data(:,1))

    if ~strcmpi(data{i-1,1},data{i,1})
        out = [out;data(i,:)];
    end

end

[Victoria Lawlor]

Thanks for the answer! This isn't working for me. Could you explain what you're doing in the loop so I can try to figure out what's going wrong?

[TastyPastry]

I'll attach the two files I wrote.

So I've got a text file which is formatted the way you wrote it. Maybe you have it as a .csv, in which case you'll need to call textscan() with commas as the delimiters.

I'm reading the data into a cell array of strings and then running a loop for all rows. I'm always going to include the first row, so I just set my output to the first row. In the loop, if the current word is different from the one previously, add the current row.

[Victoria Lawlor]

hmm thanks for replying, I'm getting an error that the index exceeds matrix dimensions. I also kind of oversimplified it when I posted the questions, there are actually four columns that I have and would need be displayed but I thought if I figured out how to do it with two I could figure out how to do it with 4, could that be the issue?

[TastyPastry]

Did you run the test.m with test.txt? I just the script and it's working fine. I doubt it's an issue with more than 1 column, since the code limits the data it pulls to the first two.