How do I plot time (hh:mm:ss.000) vs samples as imported from a .csv file?

Please see the attached .csv file. I am trying to read time (hh:mm:ss.000) and plot it vs Sample 1 or Sample 2. 000 are milliseconds. The issue I have is that when I read time with the import tool, it gets read as a constant variable. How do I read time and plot it with the file formatting vs my samples? If the import tool can't read time in this format, how do I import time with the specified formatting as a variable to plot against my samples? I am using Matlab version R2016a.

Thank you for your time.

Answer 1

[Benjamin Kraus]

If you upgrade to R2018a, this process is a little more straightforward, but this code will work in R2016a.

Step 1: Import your data and update the variable names:

t = readtable('Test.csv','ReadVariableNames',true);
t.Properties.VariableNames{1} = 'Time';

Step 2: Convert the first column to duration. I cheat a little and use datetime to do the conversions. Note that this step is done automatically in R2018a, so you can skip it. In addition, in R2018a, you can do the conversion by calling duration directly, instead of using datetime.

t.Time= datetime(t.Time,'InputFormat','HH:mm:ss.SSS')-datetime('today');
t.Time.Format = 'hh:mm:ss.SSS';

Step 3: Plot

plot(t.Time, [t.Sample1 t.Sample2],'.-');

[Jorge Zambrano]

This method worked beautifully. Thank you Benjamin.

[Venkatapathi]

To understand this code, what concepts should i learn from MATLAB?