Confusion manipulating timestamp and plotting

2 views (last 30 days)
erkelly on 4 Dec 2019
Commented: erkelly on 5 Dec 2019
I'm having issues wtih a dataset that was generated by a collaborator and given to us. We have values like the following for time:
0.0517361112797516
0.0520833335031057
0.0524305557264597
0.0527777779498138
0.0531250001731678
0.0534722223965218
0.0538194446198759
0.0541666668432299
0.0545138890665839
0.0548611112899380
0.0552083335132920
I want to be able to plot my data by HH:MM:SS.
I've been able to convert this to a string using datestr(X, 'HH:MM:SS') -- just HH:MM:SS becasue I'm 99% sure the date is completely wrong, but maybe I should keep date because the data spans 2 or 3 days? I am having trouble plotting my results based on hours/minutes/seconds because the value returned is a char / string. I've played around with datnum and others but no luck.

Jeremy on 4 Dec 2019
Is each number supposed to represent a datetime as a "datenum" data type?
t = 0.0517361112797516;
d = datetime(t,'ConvertFrom','datenum')
returns
d =
datetime
31-Dec--0001 01:14:30
And then
ds = datestr(d,'HH:MM:SS')
returns
ds =
'01:14:30'
Is this correct?
2 CommentsShowHide 1 older comment
erkelly on 5 Dec 2019
Thank you for your response!
Initially I converted all that data using the datestr, it can be converted directly
d = datestr(d,'mm-dd-yyyy HH:MM:SS');
ds = datetime(v2_1OD(:,1),'convertFrom', 'datenum');
plot(ds, y)
datetick('x', 'HH')
This plots everything and displays hours, but I also want it to plot absolute time rather than hours 0 4 8 12 16 20 24 for 3 separate days.
The strtok command didn't work for me, when I had [h,s]=strtok(d,':')
I did manage to get [h, m, s] = hms(ds) to work. Now I have to figure out the best way to make this absolute values and plot that. I could just convert all values to 'hours' and add them all together, and then add 24 and 48 to the 2nd and third day values. What do you think?

R2018b

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