Loop for removing values from a column vector
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Hi all!
So I have a column vector that I imported from Excel spreadsheet with a certain amount of values (3000 something). What I'm trying to do is create a script with a loop that will go through every value in the vector and if the value of element k is <= than the value of element k-1, it deletes this value and goes to the next one.
Example: column_vector = [1 2 1 3 7 7 5 4 8 6 9 2] -------------> new_column_vector = [1 2 3 7 8 9]
Basicaly I want it to go up withou oscilating. Any help is appreciated (I havent touched Matlab for at least 5 years)
采纳的回答
column_vector = [1 2 1 3 7 7 5 4 8 6 9 2];
logInd = [1 diff(column_vector)]>0; % Since diff will have n-1 values, prepend with 1
new_column_vector = column_vector(logInd)
6 个评论
Nikita Kaminskyy
2020-12-10
It works for the example you've provided, as you can see.
The error sounds like your data is a column vector instead of a row vector. In that case, make logInd a column vector as well (use [1; ...] instead of [1 ...]).
column_vector = [1 2 1 3 7 7 5 4 8 6 9 2]';
logInd = [1; diff(column_vector)]>0; % Since diff will have n-1 values, prepend with 1
new_column_vector = column_vector(logInd)
Nikita Kaminskyy
2020-12-10
It is not specific to integers, but it only looks at immediate neighbors. That could lead to a scenario where the final vector in not always strictly increasing.
I think a better solution would use cummax. This will give you the running max. I use unique to removed duplicates.
column_vector = rand(10,1)*10
new_column_vector = unique(cummax(column_vector))
Nikita Kaminskyy
2020-12-10
Nikita Kaminskyy
2020-12-10
更多回答（1 个）
Fangjun Jiang
2020-12-10
%%
v=[1 2 1 3 7 7 5 4 8 6 9 2];
for k=length(v):-1:2
if v(k)<=v(k-1)
v(k)=[];
end
end
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