Add missing time data

Question

Tiago Dias 2017-12-19

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评论： Walter Roberson 2017-12-20

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Hello, i have in excel 2 columns, A for time data DD/MM/YYYY HH:MM:SS and the other column are values from a variable X1.

and i want to create all the missing data time with a frequency of 1 min, and the X1 value being a blank cell or N/A something like that.

I have tried with a excel macro vba, but the excel always crashes so i wanted to know if it is possible to do that in matlab

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Answer 1

Peter Perkins 2017-12-19

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在 MATLAB Online 中打开

Your data run from 1-Jan-2016 to 31-Dec-2016. There are

>> minutes(diff(datetime(2016,[1 12],[1 31])))
ans =
      525600

minutes in 2016. Do you really want that many rows? You can do it, but let's assume you really meant every 30 minutes. Using timetables, introduced in R2016b,

>> t = table2timetable(readtable('U1200 - Massa Vol£mica (1).xlsx'));
>> head(t)
ans =
  8×1 timetable
            Date              X1  
    ____________________    ______
    01-Jan-2016 00:00:00         0
    03-Jan-2016 05:00:00    0.7353
    04-Jan-2016 04:30:00    0.7338
    08-Jan-2016 04:30:00    0.7404
    11-Jan-2016 04:30:00    0.7393
    13-Jan-2016 11:30:00     0.736
    15-Jan-2016 04:30:00    0.7356
    18-Jan-2016 04:30:00    0.7398
>> regularTimes = datetime(2016,1,1,'Format','dd-MMM-yyyy HH:mm:ss'):minutes(30):datetime(2016,12,13,23,30,0);
>> t2 = retime(t,regularTimes);
>> head(t2)
ans =
  8×1 timetable
            Date            X1 
    ____________________    ___
    01-Jan-2016 00:00:00      0
    01-Jan-2016 00:30:00    NaN
    01-Jan-2016 01:00:00    NaN
    01-Jan-2016 01:30:00    NaN
    01-Jan-2016 02:00:00    NaN
    01-Jan-2016 02:30:00    NaN
    01-Jan-2016 03:00:00    NaN
    01-Jan-2016 03:30:00    NaN