Read in timestamps from weird time format

Hello! I am trying to read in data collected in CA. The timestamps are UTC times recorded as a string that includes characters I do not need. Can you help me figure out how to read in a column of timestamps that look likes this (see below). I want to end up with mtimes or even just separate the timestamps parts so that I can use datenum myself to reconnect the parts. Thank you! This is a column in a csv file if that makes a difference.

'2015-05-07T05:48:59Z'

'2015-05-07T05:58:59Z'

'2015-05-07T06:18:59Z'

'2015-05-07T06:28:58Z'

'2015-05-07T06:38:59Z'

'2015-05-07T06:48:59Z'

'2015-05-07T06:58:59Z'

'2015-05-07T07:08:58Z'

'2015-05-07T07:18:59Z'

'2015-05-07T07:28:59Z'

'2015-05-07T07:38:59Z'

'2015-05-07T07:48:59Z'

'2015-05-07T07:58:59Z'

'2015-05-07T08:08:58Z'

'2015-05-07T08:18:59Z'

'2015-05-07T08:28:59Z'

'2015-05-07T08:38:59Z'

'2015-05-07T08:48:59Z'

'2015-05-07T08:58:59Z'

'2015-05-07T09:08:58Z'

[Stephen23]

That is not a "weird time format" at all, they appear to be quite normal ISO 8601 timestamps:

https://en.wikipedia.org/wiki/ISO_8601

ISO 8601 date formats are preferred for any situtuation where it is required to write dates that will be universally understood (e.g. data collection, filenames, data exchange, internet protocols, documentation, published articles, etc). Their ability to be sorted into chronological order with a basic character-sort makes them much more convenient to work with than any other date formats.

https://xkcd.com/1179/

Answer 1

[Walter Roberson]

If the data is stored in a cell array of character vectors, S, then

datetime(S, 'InputFormat', 'uuuu-MM-dd''T''hh:mm:ss''Z''', 'TimeZone', 'UTC')

[Heidi Hirsh]

Thank you Walter! Just to clarify, is S my vector of times? I saved my times as 'timestring' then ran this:

time = datetime(timestring, 'InputFormat', 'uuuu-MM-dd''T''hh:mm:ss''Z''', 'TimeZone', 'UTC');

But 'time' does not look right and I have a lot of NaT values.

[Heidi Hirsh]

This is the data I'm working with if it helps...

[Walter Roberson]

T = readtable('M1_buoy/m1buoydata.csv');
time = datetime(T.date_time, 'InputFormat', 'uuuu-MM-dd''T''HH:mm:ss''Z''', 'TimeZone', 'UTC');

[Heidi Hirsh]

Thank you! I thought I had essentially done that. This is what I had:

m1data = readtable('M1_buoy/m1buoydata.csv'); 
timestring = m1data.date_time; %times are UTC
%need to reformat time from this: {'2015-05-07T06:28:58Z'}
time = datetime(timestring, 'InputFormat', 'uuuu-MM-dd''T''hh:mm:ss''Z''', 'TimeZone', 'UTC');

But I reran it using your code and now the timestamps look fine. Thanks so much!

[Walter Roberson]

I had accidentally used hh where I should have used HH. With datetime(), hh is for 12 hour times, and HH is needed for 24 hour times.