MATLAB: A second basic ‘Find’ question

find

I want to identify starting point of a range of values whereby the first value is greater than or equal to X and all subsequent values are greater than another value (Y), which smaller than X. The exact length of the range isn't known exactly (it has at least N points) no other data range of similar length or longer occurs within the data set.

For example: 1, 2, 3, 4, 5,6,3.5,3.1, 7,6,8,6,5,3,1,2,3,4, X=4 Y=3 N=5 I want to find the range which starts greater than or equal to 4 and doesn't fall below 3. I know that there are at least 5 data points within the range of interest.

Best Answer

idx = findstr([0 data>=X],[0 1]);
idx = idx(ismembc(idx,findstr(data>Y,ones(1,N))))

Related Solutions

MATLAB: Finding the number of consecutive points in a given vector, using a condition

with function regionprops from Image Processing Toolbox

idx = regionprops(A<1,'Area','PixelIdxList');
out = cellfun(@(x)A(x),{idx([idx.Area] > 3).PixelIdxList},'un',0);

other way

t = A<1;
z = [find([true,diff(t)~=0]) numel(A)+1];
idx = [z(1:end-1);z(2:end)-1];
i1 = idx(:,t(idx(1,:)));
i2 = i1(:,(diff(i1) + 1) > 3);
out = arrayfun(@(x)A(i2(1,x):i2(2,x)),1:size(i2,2),'un',0);

third way

t = A<1;
t1 = [~t(1) t ~t(end)];
idx = [strfind(t1,[0 1]);strfind(t1,[1 0])-1];
i1 = idx(:,diff(idx) + 1 > 3);
out = arrayfun(@(x)A(i2(1,x):i2(2,x)),1:size(i2,2),'un',0);

MATLAB: Replacing values from a separate vector to multiple repeated values in another vector

index=find(x==0);
idx=find(diff(index)~=1);
z=x;
z(z==0)=repelem(y,[idx(1) diff(idx) numel(index)-idx(end)]);
z(z==1)=0

Best Answer

Related Solutions

MATLAB: Finding the number of consecutive points in a given vector, using a condition

MATLAB: Replacing values from a separate vector to multiple repeated values in another vector

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