Error using datenum (line 201) DATENUM failed.

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I have this error, and I don't know why.
Error using datenum (line 201)
DATENUM failed.
Caused by:
Error using dtstr2dtnummx
Failed to convert from text to date number.
My script is this:
[ndata, text, alldata]=xlsread('positive_read_Copia.xlsx'); % inside there are data (dd/mm/yyyy hh:mm:ss) and coordinates
date=date.';
tmp=char(date);
tmp_date=datenum(tmp,'dd/mm/yyyy HH:MM');
DateVector = datevec(tmp_date);
Date_minute=(tmp_date-tmp_date(1))*24*60; % Time, in minutes compared to the 1st georeferenced tweet
clear tmp;

Answers (1)

Stephen23
Stephen23 on 18 Nov 2021
Edited: Stephen23 on 18 Nov 2021
Do not use outdated, discouraged, deprecated DATENUM (or for that matter DATEVEC or DATESTR).
Import your data using READTABLE, which automatically identifies the dates and imports them as DATETIME objects:
T = readtable('positive_read_Copia.xlsx')
T = 1108×3 table
tweet_created_at Latitude Longitude ____________________ ________ _________ 28-Sep-2020 01:13:00 4.8186 45.728 28-Sep-2020 02:11:00 -80.217 25.783 28-Sep-2020 03:20:00 4.4894 45.895 28-Sep-2020 08:38:00 -74.245 40.617 28-Sep-2020 09:32:00 4.0817 44.128 28-Sep-2020 09:46:00 4.0817 44.128 28-Sep-2020 10:20:00 103.45 35.845 28-Sep-2020 10:22:00 4.0817 44.128 28-Sep-2020 10:41:00 2.5067 49.098 28-Sep-2020 11:55:00 6.8992 49.53 28-Sep-2020 12:34:00 15.314 -4.3317 28-Sep-2020 12:50:00 35.25 32 28-Sep-2020 13:46:00 -14.75 16.5 28-Sep-2020 14:05:00 2 47 28-Sep-2020 14:36:00 7.4167 43.733 28-Sep-2020 16:24:00 9.2167 45.617
Then your task is much easier too, simply subtract to get the differences as DURATION objects:
D = T.tweet_created_at - T.tweet_created_at(1)
D = 1108×1 duration array
00:00:00 00:58:00 02:07:00 07:25:00 08:19:00 08:33:00 09:07:00 09:09:00 09:28:00 10:42:00 11:21:00 11:37:00 12:33:00 12:52:00 13:23:00 15:11:00 15:24:00 15:42:00 16:55:00 18:10:00 18:15:00 21:16:00 21:26:00 22:42:00 30:23:00 31:14:00 32:11:00 32:23:00 37:02:00 37:55:00
which is then trivial to convert into MINUTES:
M = minutes(D)
M = 1108×1
0 58 127 445 499 513 547 549 568 642
  4 Comments
Rachele Franceschini
Rachele Franceschini on 18 Nov 2021
Error is: I have the map and the graph empty.

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