# Find datapoints a specified distance apart in matrix using while loop

1 view (last 30 days)
Emu on 27 Mar 2023
Commented: Emu on 27 Mar 2023
I have some data with positive integers (to_pos). I want to find and extract into a second matrix (spacedCrossPoints) datapoints that are a minimum of 30 from each other. So my desired output would be: 1214,2263,2320,8262,8292....
Here is my not working code so far:
gapBetweenCrosses = 30;
for cross = 2:length(t0_pos)-1;
i = cross;
if (((t0_pos(cross+1))-(t0_pos(i))) >= gapBetweenCrosses)% && (cross < ((length(t0_pos))-30)); %if gap between row greater than or equal to 30(s)
spacedCrossPoints(end+1,1) = t0_pos(cross+1); %insert values of crosspoints into matrix
elseif ((t0_pos(cross+1))) - (t0_pos(i)) < gapBetweenCrosses %&& cross < (length(t0_pos))-30; %if gap is less than 30. skips
%jump = 30-(((t0_pos(cross+1))) - (t0_pos(cross))); %calculate jump as difference between 30 and different between rows
while ((t0_pos(cross+1))) - (t0_pos(i)) < gapBetweenCrosses
cross = cross+1;
%spacedCrossPoints(end+1,1) = t0_pos(cross+1); %notes new value 30 past last value %NEED TO MAKE CROSS NOT EXCEED length t0_pos
end
end
cross = cross+1;
end
end
##### 2 CommentsShow 1 older commentHide 1 older comment
Emu on 27 Mar 2023
In the attached dataset the datapoints that are 30 or more points from each other are as specified: 1214,2263,2320,8262,8292... They are not pairs.

Dyuman Joshi on 27 Mar 2023
Edited: Dyuman Joshi on 27 Mar 2023
Points which are >= 30 than the previous point starting with the 1st point -
gap=30;
k=1;
y=false(size(t0_pos));
y(k)=true;
%loop
while k<numel(t0_pos)
k=find(t0_pos - t0_pos(k) >= gap, 1);
y(k)=true;
end
out = t0_pos(y)'
out = 1×34
1214 2263 2320 8262 8292 8322 8434 8480 9014 9090 9149 9179 9215 14848 14904 15106 15149 15207 15372 15443 16330 16671 16708 20532 20590 20757 20809 23325 23355 23385
Emu on 27 Mar 2023
that is amazing :) thank you so much !!

### Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

R2022b

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!