How to use str2num function to extract a specific year from the array?

Hi!

I have a column matrix consists of string arrays. It's a huge time matrix and I am just showing a part of it. It contains data from year 2001 to 2019.

'2003-09-30T20:32:34Z'
'2003-09-30T20:47:34Z'
'2003-09-30T21:02:34Z'
'2003-09-30T21:17:34Z'
'2003-09-30T21:32:34Z'
'2003-09-30T21:47:34Z'
'2003-09-30T22:02:34Z'
'2003-09-30T22:17:34Z'
'2003-09-30T22:32:34Z'
'2003-09-30T22:47:34Z'
'2003-09-30T23:02:34Z'
'2003-09-30T23:17:34Z'
'2003-09-30T23:32:34Z'
'2003-09-30T23:47:34Z'
'2004-05-23T13:45:00Z'
'2004-05-23T14:00:00Z'
'2004-05-23T14:15:00Z'
'2004-05-23T14:30:00Z'
'2004-05-23T14:45:00Z'
'2004-05-23T15:00:00Z'
'2005-05-23T15:15:00Z'
'2005-05-23T15:30:00Z'
'2005-05-23T15:45:00Z'
'2005-05-23T16:00:00Z'
'2005-05-23T16:15:00Z'
'2005-05-23T16:30:00Z'
'2006-05-23T16:45:00Z'
'2006-05-23T17:00:00Z'
'2006-05-23T17:15:00Z'
'2006-05-23T17:30:00Z'
'2006-05-23T17:45:00Z'
'2007-05-23T18:00:00Z'

If I want to extract only the data from 2003, how can I select those specific rows of 2003? I personally want to use this command -

str2num(time{i}(1:4))==2003

But if there is a better alternative, I am happy to use it! Thank you so much.

Answer 1

[Star Strider]

C =    {'2003-09-30T20:32:34Z'
        '2003-09-30T20:47:34Z'
        '2003-09-30T21:02:34Z'
        '2003-09-30T21:17:34Z'
        '2003-09-30T21:32:34Z'
        '2003-09-30T21:47:34Z'
        '2003-09-30T22:02:34Z'
        '2003-09-30T22:17:34Z'
        '2003-09-30T22:32:34Z'
        '2003-09-30T22:47:34Z'
        '2003-09-30T23:02:34Z'
        '2003-09-30T23:17:34Z'
        '2003-09-30T23:32:34Z'
        '2003-09-30T23:47:34Z'
        '2004-05-23T13:45:00Z'
        '2004-05-23T14:00:00Z'
        '2004-05-23T14:15:00Z'
        '2004-05-23T14:30:00Z'
        '2004-05-23T14:45:00Z'
        '2004-05-23T15:00:00Z'
        '2005-05-23T15:15:00Z'
        '2005-05-23T15:30:00Z'
        '2005-05-23T15:45:00Z'
        '2005-05-23T16:00:00Z'
        '2005-05-23T16:15:00Z'
        '2005-05-23T16:30:00Z'
        '2006-05-23T16:45:00Z'
        '2006-05-23T17:00:00Z'
        '2006-05-23T17:15:00Z'
        '2006-05-23T17:30:00Z'
        '2006-05-23T17:45:00Z'
        '2007-05-23T18:00:00Z'};

DT = datetime(C, 'InputFormat','yyyy-MM-dd''T''HH:mm:ss''Z''', 'TimeZone','UTC')        % Create 'datetime' Array

DT = 32×1 datetime array
   30-Sep-2003 20:32:34
   30-Sep-2003 20:47:34
   30-Sep-2003 21:02:34
   30-Sep-2003 21:17:34
   30-Sep-2003 21:32:34
   30-Sep-2003 21:47:34
   30-Sep-2003 22:02:34
   30-Sep-2003 22:17:34
   30-Sep-2003 22:32:34
   30-Sep-2003 22:47:34
   30-Sep-2003 23:02:34
   30-Sep-2003 23:17:34
   30-Sep-2003 23:32:34
   30-Sep-2003 23:47:34
   23-May-2004 13:45:00
   23-May-2004 14:00:00
   23-May-2004 14:15:00
   23-May-2004 14:30:00
   23-May-2004 14:45:00
   23-May-2004 15:00:00
   23-May-2005 15:15:00
   23-May-2005 15:30:00
   23-May-2005 15:45:00
   23-May-2005 16:00:00
   23-May-2005 16:15:00
   23-May-2005 16:30:00
   23-May-2006 16:45:00
   23-May-2006 17:00:00
   23-May-2006 17:15:00
   23-May-2006 17:30:00

Y2003 = year(DT) == 2003;                                                               % Logical Vector

Result = DT(Y2003)

Result = 14×1 datetime array
   30-Sep-2003 20:32:34
   30-Sep-2003 20:47:34
   30-Sep-2003 21:02:34
   30-Sep-2003 21:17:34
   30-Sep-2003 21:32:34
   30-Sep-2003 21:47:34
   30-Sep-2003 22:02:34
   30-Sep-2003 22:17:34
   30-Sep-2003 22:32:34
   30-Sep-2003 22:47:34
   30-Sep-2003 23:02:34
   30-Sep-2003 23:17:34
   30-Sep-2003 23:32:34
   30-Sep-2003 23:47:34

For table ‘T1’, the addressing would be:

Result = T1(Y2003,:)

to capture all the variables in ‘T1’ for those years.

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