Index satisfying multiple conditions

Hi, I have a matrix with 4 columns of Year, Month, Hour, Speed. I would like to extract the data from just month 1, month 11 and month 12. My code is as below:

 Wind_All = [year month day speed];
 loc = find(Wind_All(:,2)==1 & Wind_All(:,2)>=11);

 YEAR = [year(loc(1):max(loc))];
 MONTH = [month(loc(1):max(loc))];
 DAY = [day(loc(1):max(loc))];
 SPEED = [speed(loc(1):max(loc))];

However, it's giving me an error message:

Index exceeds matrix dimensions. Error in Speed_Bin6 (line 34); YEAR = [year(loc(1):max(loc))];

Can someone tell me what I did wrong there? It works if it's:

loc = find(Wind_All(:,1)==2015 & Wind_All(:,2)>=11); &&indexing year 2015 and month 11 and 12.

Thank you!

Answer 1

[Guillaume]

I do not really understand what you are trying to do with the loc(1):max(loc) bit.

As Elias says, you want | instead of &. But note that you also did not need the find:

Wind_All = [year month day speed];
loc = Wind_All(:, 2) == 1 | Wind_All(:, 2) >= 11;  %No need for find. Use logical indexing instead

filtered = Wind_All(loc, :)

And personally, I would use ismember instead of your logical expression:

Wind_All = [year month day speed];
loc = ismember(Wind_All(:, 2), [1, 11, 12]);

filtered = Wind_All(loc, :)

[NMans]

Thanks these also work!!

Answer 2

[Elias Gule]

Just replace the '&' with '|'. Because you want the value in column 2 where the month is 1 or where the month is greater or equal to 11.

[NMans]

thanks this works!