MATLAB: Remove outlier in large data

outlier std mean

my question how to find outlier in matlab explain by code and example ? and how many methods ? how to find outlier?

Best Answer

Try this:

% data = the variable name of your array
stdDev = std(data(:)) % Compute standard deviation
meanValue = mean(data(:)) % Compute mean
zFactor = 1.5; % or whatever you want.
% Create a binary map of where outliers live.
outliers = abs(data-meanValue) > (zFactor * stdDev);

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MATLAB: How to replace messy data by using linear interpolation of nearby messy data

Replace all ****** values in the text file with NaN's and follow the below code:

data = importdata('data.txt') ;
data = data.data ;
t = data(:,1) ; 
s1 = data(:,2) ; 
s2 = data(:,3) ;
%% Remove outliers in s1
stdDev = nanstd(s1) ;% Compute standard deviation

meanValue = nanmean(s1) ; % Compute mean

zFactor = 1.5; % or whatever you want.

% Create a binary map of where outliers live.

outliers = abs(s1-meanValue) > (zFactor * stdDev);
s1(outliers) = NaN ;
% GEt NaN filled 

idx = isnan(s1) ;
s1(idx) = interp1(t(~idx),s1(~idx),t(idx)) ;
%% Remove outliers in s2
stdDev = nanstd(s2) ;% Compute standard deviation
meanValue = nanmean(s2) ; % Compute mean
zFactor = 1.5; % or whatever you want.
% Create a binary map of where outliers live.
outliers = abs(s2-meanValue) > (zFactor * stdDev);
s2(outliers) = NaN ; 
% GEt NaN filled 
idx = isnan(s2) ;
s2(idx) = interp1(t(~idx),s2(~idx),t(idx)) ;

MATLAB: How to make array from characters from variables

Create a cell array out of the character array:

c = cellstr(val);

Then, each cell element is a string that can be used:

c{1}

for example, is the first string. (Notice the use of curly brackets there.) You can read more about the use of cell array in the documentation.

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MATLAB: How to replace messy data by using linear interpolation of nearby messy data

MATLAB: How to make array from characters from variables

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