Please how i can set the indexes of a vector or matrix in Matlab (exactly like the function set index in python)

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Inouss
Inouss on 10 Mar 2020
Commented: Luna on 1 Jun 2020
I have a csv file which has 2 columns and I want to put the first column as an index so that I can synchronize it with another file. Please Please if anyone has any idea how to do it on matlab
  5 Comments
Luna
Luna on 10 Mar 2020
Is first column miliseconds? It goes like that:
1303132929
1303132930
1303132931
1303132932
Also how do you want to synchronize or resample these 2 tables? How do you want to fill your missing values? Do you have sampling rate?

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Accepted Answer

Luna
Luna on 10 Mar 2020
Hello,
I wrote some codes for you and I am going to share some links so that you can read in documentation and it will help.
Please read my comments below:
chan1_table = readtable('chan1.csv'); % read table 1. Your files must be in your work folder, otherwise use full path name.(Ex: 'C:/Users/.../chan1.csv')
chan2_table = readtable('chan2.csv'); % read table 2
% your both table have Var1 and Var2 variables. Var1 variables are your
% time column.
chan1_table.Var1 = milliseconds(chan1_table.Var1); % convert Var1 into milliseconds. You can use seconds, minutes or any other duration functions.
chan2_table.Var1 = milliseconds(chan2_table.Var1); % same as chan1_table.
%% convert both tables to time table according to their time column.
TT1 = table2timetable(chan1_table,'RowTimes','Var1');
TT2 = table2timetable(chan2_table,'RowTimes','Var1');
%% choose a time step
dt = milliseconds(1); % I choose 1 milliseconds because I don't know what it is. You can change as you wish.
% For example: dt = seconds(10)
% synchronize your table like below:
synched_table = synchronize(TT1,TT2,'regular','nearest','TimeStep',dt); % you can also use 'SampleRate',Fs. Fs must be in Hz(frequency)

More Answers (1)

David Hill
David Hill on 10 Mar 2020
B=zeros(max(A(:,1)),1);
B(A(:,1))=A(:,2);
If you don't like all the zeros, then you could use a sparse matrix.
B=sparse(A(:,1),1,A(:,2));

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