sorting table according to date/time

Hi,

I have a table with a TimeStamp column with the format '6/29/2020 12:39:32.910 AM'. I want to sort the table in acesending order but by default Matlab treats the column as a string. I have tried using datetime to define the column as dat format:

>> t=datetime(T1T2.TimeStamp,'InputFormat', 'MM/DD/yyyy HH:mm:ss.sss')

which failed, probably becasue I am not defining the AM/PM symbols.

What is the best/easiest way to sort this table according to the date value?

Many thanks,

Ben

Answer 1

[Star Strider]

There are problems with the 'InputFormat' format string.

Try this:

t=datetime(T1T2.TimeStamp,'InputFormat', 'MM/dd/yyyy hh:mm:ss.SSS a')

producing:

t = 

  datetime

   29-Jun-2020 00:39:32

Note that the hours need to be ‘hh’ not ‘HH’ for AM/PM times, the days are ‘dd’ not ‘DD’, and the ‘a’ denotes that the format is in AM/PM. (I created a temporary variable to replace the table reference to test this and make certain that it works.)

Answer 2

[Steven Lord]

which failed, probably becasue I am not defining the AM/PM symbols.

According to the table in the description of the Format property of datetime objects include the character a in the Format and/or InputFormat values to handle AM/PM. I had to make three additional changes to your InputFormat, each prompted by a warning and/or error message.

Using HH for hours in 24-hour clock notation is incompatible with also specifying the day period (AM/PM) so I changed it to hh (hour, 12-hour clock notation.)

Using MM (month) and DD (day of year) are incompatible, so I changed DD to dd (day of month).

Lower-case ss is for seconds, upper-case S are for the digits of fractional seconds.

 s = '6/29/2020 12:39:32.910 AM'
 t=datetime(s,'InputFormat', 'MM/dd/yyyy hh:mm:ss.SSS a')

Answer 3

[KSSV]

Convert the dates you have into class of datetime using the function datetime and then you can use sort function. Read about datetime.

Answer 4

[Carol pacheco]

Hello,

I have a dataset that I need to group the data into over a period of fifteen days (two weeks), however I have a total of 23 weeks. Could someone give me a little help or guidance ?