Iterating through Matlab Table

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Metin Akyol
Metin Akyol 2022-2-24
评论： Metin Akyol 2022-2-25
I have a simple Matlab table with dates and 2 additional columns that contain numbers and strings. The dates are NOT daily, that is sometimes multple days are missing.
I would like to forward fill the table such that the table becomes a daily table and for each day that is missing, the rows from the previous date are copied.

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采纳的回答

KSSV
KSSV 2022-2-24
LEt T be your table. With first column as dates.
% First make the dates daily
thedates = T.(1) ; % existing dates of the table
thedates_new = (thedates(1):thedates(2))' ; % Make daily dates
% GEt the existing dates indices
[idx,ia] = ismember(thedates_new,thedates) ;
C2 = T.(2) ; % second column of table
C2_new = NaN(size(thedates_new)) ;
C2_new(idx) = C2;
C2_new = fillmissing(C2_new) ;
T_new = table(thedates_new,C2_new) ;
Alternatively you may have a look on the function retime

更多回答（2 个）

Seth Furman
Seth Furman 2022-2-25
Ran in:
timetable has a retime method that supports resampling by copying the previous value.
Resample or aggregate data in timetable, and resolve duplicate or irregular times - MATLAB retime (mathworks.com)
tt = timetable(datetime(2020,1,[1;3;4;7;9]), [1;3;4;7;9])
tt = 5×1 timetable
Time Var1 ___________ ____ 01-Jan-2020 1 03-Jan-2020 3 04-Jan-2020 4 07-Jan-2020 7 09-Jan-2020 9
retime(tt, "daily", "previous")
ans = 9×1 timetable
Time Var1 ___________ ____ 01-Jan-2020 1 02-Jan-2020 1 03-Jan-2020 3 04-Jan-2020 4 05-Jan-2020 4 06-Jan-2020 4 07-Jan-2020 7 08-Jan-2020 7 09-Jan-2020 9
Arif Hoq
Arif Hoq 2022-2-24
Ran in:
date = {'2014-05-20';'2014-05-21';'2014-05-22';'2014-05-24';'2014-05-25'}; % define the date
name = {'Sanchez';'Johnson';'Li';'Diaz';'Brown'}; % define the string
age = [38;43;38;40;49]; % define the numerical
T=table(date,name,age) % make a table
T = 5×3 table
date name age ______________ ___________ ___ {'2014-05-20'} {'Sanchez'} 38 {'2014-05-21'} {'Johnson'} 43 {'2014-05-22'} {'Li' } 38 {'2014-05-24'} {'Diaz' } 40 {'2014-05-25'} {'Brown' } 49
idx = diff(datenum(T.date, 'yyyy-mm-dd')).'==1; % return the missing date
idx2=find(idx==0); % missing date index
newdate=[T.date(1:idx2);T.date(idx2);T.date(idx2+1:end)]; % concatenate the date
newname=[T.name(1:idx2);T.name(idx2);T.name(idx2+1:end)]; % concatenate the name
newage=[T.age(1:idx2);T.age(idx2);T.age(idx2+1:end)]; % concatenate the age
newTable=table(newdate,newname,newage) % newtable
newTable = 6×3 table
newdate newname newage ______________ ___________ ______ {'2014-05-20'} {'Sanchez'} 38 {'2014-05-21'} {'Johnson'} 43 {'2014-05-22'} {'Li' } 38 {'2014-05-22'} {'Li' } 38 {'2014-05-24'} {'Diaz' } 40 {'2014-05-25'} {'Brown' } 49

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