How to extract date, month, year, and time from a table data?

I have a table data like "A" like this:

>> A(1:49,1)

ans =

  49×1 table

         DateTime      
    ___________________

    2016-01-01 00:30:00
    2016-01-01 01:00:00
    2016-01-01 01:30:00
    2016-01-01 02:00:00
    2016-01-01 02:30:00
    2016-01-01 03:00:00
    2016-01-01 03:30:00
    2016-01-01 04:00:00
    2016-01-01 04:30:00
    2016-01-01 05:00:00
    2016-01-01 05:30:00
    2016-01-01 06:00:00
    2016-01-01 06:30:00
    2016-01-01 07:00:00
    2016-01-01 07:30:00
    2016-01-01 08:00:00
    2016-01-01 08:30:00
    2016-01-01 09:00:00
    2016-01-01 09:30:00
    2016-01-01 10:00:00
    2016-01-01 10:30:00
    2016-01-01 11:00:00
    2016-01-01 11:30:00
    2016-01-01 12:00:00
    2016-01-01 12:30:00
    2016-01-01 13:00:00
    2016-01-01 13:30:00
    2016-01-01 14:00:00
    2016-01-01 14:30:00
    2016-01-01 15:00:00
    2016-01-01 15:30:00
    2016-01-01 16:00:00
    2016-01-01 16:30:00
    2016-01-01 17:00:00
    2016-01-01 17:30:00
    2016-01-01 18:00:00
    2016-01-01 18:30:00
    2016-01-01 19:00:00
    2016-01-01 19:30:00
    2016-01-01 20:00:00
    2016-01-01 20:30:00
    2016-01-01 21:00:00
    2016-01-01 21:30:00
    2016-01-01 22:00:00
    2016-01-01 22:30:00
    2016-01-01 23:00:00
    2016-01-01 23:30:00
    2016-01-02 00:00:00
    2016-01-02 00:30:00
    

This is a very large array containing time stamp for every half hour interval for 2 year duration. I wanted to extract the year (say 2016), day (say 1), month (say 1), and time (say 00:30 as 0.5) from this table data. How to do the same? Kindly help me.

Answer 1

[VBBV]

A = string({'2016-01-09 00:30:00';'2017-05-10 01:00:00'});
At = table(A,'VariableNames',{'Time'}); 
for k = 1:length(At.Time)
    Y(k) = datetime(At.Time(k),'Format','yyyy');  % year
    M(k) = datetime(At.Time(k),'Format','MM');   % month
    D(k) = datetime(At.Time(k),'Format','dd');   % day
    H(k) = datetime(At.Time(k),'Format','hh:mm');  % time
end
Y, M, D , H

Y = 2×1 datetime array
   2016
   2017

M = 1×2 datetime array
   01   05

D = 1×2 datetime array
   09   10

H = 1×2 datetime array
   12:30   01:00

[Stephen23]

This code simply changes the formatting, but the underlying date/time data is still stored in the DATETIME object. So it does not actually "extract the year ... day .. month ... and time ... from this table data", it just changes how the DATETIME object is displayed.

Answer 2

[Stephen23]

The MATLAB approach is to use YMD() and TIMEOFDAY() and HOURS():

S = ["2016-01-01 00:30:00"; "2016-01-01 01:00:00"; "2016-01-01 01:30:00"; "2016-01-01 02:00:00"; "2016-01-01 02:30:00"; "2016-01-01 03:00:00"; "2016-01-01 03:30:00"];
T = datetime(S)

T = 7×1 datetime array
   01-Jan-2016 00:30:00
   01-Jan-2016 01:00:00
   01-Jan-2016 01:30:00
   01-Jan-2016 02:00:00
   01-Jan-2016 02:30:00
   01-Jan-2016 03:00:00
   01-Jan-2016 03:30:00

[Y,M,D] = ymd(T)

Y = 7×1

2016 2016 2016 2016 2016 2016 2016

M = 7×1

1 1 1 1 1 1 1

D = 7×1

1 1 1 1 1 1 1

H = hours(timeofday(T))

H = 7×1

0.5000 1.0000 1.5000 2.0000 2.5000 3.0000 3.5000