Assign NaN to specific rows(based on criteria) for multiple table variables
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I want to assign NaN to (time-)table rows that match a criteria (T.Var1~=1). I would like to do this for specific variables in the table.
But instead of doing
T.Var2(T.Var1~=1)=NaN; % Note: My variables are not called Var1, Var2, ... but I simplified it here to these names ;-)
T.Var5(T.Var1~=1)=NaN;
%...
T.Var10(T.Var1~=1)=NaN;
%...
I would like to do this in a shorter code. Is this possible?
I look for something like this:
T.{'Var2','Var5', 'Var7', 'Var10'}(T.Var1~=1)=NaN;
Accepted Answer
You can do that as follows:
% Firstly some sample data
T = array2timetable(randi(3,10,5),'Rowtimes',datetime() + seconds(0:9))
% You can do it using column numbers
T{T.Var1==1,[2 4]} = nan
% or using variable names
T{T.Var1==1,["Var3", "Var5"]} = nan
3 Comments
Marcel345614
on 1 Feb 2022
No problem. The single quotes are type char and the double quotes are type string. You can see why Var1Var3Var5 came up just by typing it into the command window:
idx = ['Var1' 'Var3' 'Var5']
whereas when you concatenate strings the result is different:
idx = ["Var1" "Var3" "Var5"]
You could also use a cell array of char's to index by the variable names:
T = array2timetable(randi(3,10,5),'Rowtimes',datetime() + seconds(0:9));
T{T.Var1==1,{'Var3', 'Var5'}} = nan
Marcel345614
on 2 Feb 2022
More Answers (1)
Benjamin Thompson
on 1 Feb 2022
0 votes
If you are assigning from a scalar it seems you must do this column by column. Use an index vector to select which rows to assign:
T.Var1 = [1 2 3 4 1]'
T.Var2 = 2*ones(5,1)
T.Var3 = 5*ones(5,1)
T.Var4 = 10*ones(5,1)
I = T.Var1 ~= 1
T2.Var2(I) = NaN
T2.Var3(I) = NaN
T2.Var4(I) = NaN
See the MATLAB help article "Access Data in Tables" for more data reading and writing examples.
1 Comment
Marcel345614
on 1 Feb 2022
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