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# How to plot datetime array?

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Asher Zaidi on 18 Jun 2018
Answered: Aron Magesh on 22 May 2020
I would like to plot a vector, r, as a function of time. The two vectors I have are:
r'
1.0e+03 *
0.0179
0.0180
0.0184
0.0184
0.0189
0.0189
0.0189
0.0189
0.0190
0.0190
ds =
10×1 datetime array
02-Feb-2018 11:08:11
02-Feb-2018 12:08:13
02-Feb-2018 01:08:14
02-Feb-2018 02:08:15
02-Feb-2018 03:08:17
02-Feb-2018 04:08:18
02-Feb-2018 05:08:20
02-Feb-2018 06:08:21
02-Feb-2018 07:08:23
02-Feb-2018 08:08:24
However, when I try to plot them:
plot(datenum(ds), r, '-o')
datetick('x', 'dd-mmm-yyyy HH:MM:SS')
I get this graph (see attached). I would like for each point to have a corresponding time and date on the x-axis, if it is possible.

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### Accepted Answer

Walter Roberson on 18 Jun 2018
plot(ds, rs, '-o')
From R2016b onward, you can use datetime objects as the x or y axes. (Exact release varies a bit with variety of graph being plotted.)

#### 3 Comments

Asher Zaidi on 19 Jun 2018
I get the following error:
>> plot(ds,r, '-o')
Data inputs must match the axis configuration. A numeric axis must have numeric data inputs or
data inputs which can be converted to double.
Walter Roberson on 19 Jun 2018
You could get that if you were trying to do a datetime plot on top of an existing numeric axes.
If you are trying to draw on top of an existing axes, then you might have "hold on" in effect, and that might have affected the xtick values that the axes thought should be used.
When I use your commands together with
ds = datetime({'02-Feb-2018 11:08:11'
'02-Feb-2018 12:08:13'
'02-Feb-2018 01:08:14'
'02-Feb-2018 02:08:15'
'02-Feb-2018 03:08:17'
'02-Feb-2018 04:08:18'
'02-Feb-2018 05:08:20'
'02-Feb-2018 06:08:21'
'02-Feb-2018 07:08:23'
'02-Feb-2018 08:08:24'});
r = 1e3 * [ 0.0179
0.0180
0.0184
0.0184
0.0189
0.0189
0.0189
0.0189
0.0190
0.0190];
then xtick creates labels for every 3 hours.
Asher Zaidi on 20 Jun 2018
I see, thank you!

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### More Answers (1)

Aron Magesh on 22 May 2020
If you have used hold on function, make sure to use the hold off as well to avoid this error.

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