How do I import a timestamp from Excel/csv?

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Dan Getz
Dan Getz on 6 Jul 2017
Commented: Walter Roberson on 11 Jul 2017
I have a .csv file with 6 columns of data and 14000 or so rows. I attached a file with a screenshot of the spreadsheet. I have tried
data=load('My_Spreadsheet_Name');
timestamp=data(:,1);
and since learned why that won't work. I then tried
xlsread('My_Spreadsheet_Name');
and that worked for everything that wasn't a timestamped piece of data. The 5 columns on the right imported into Matlab just fine but Matlab skipped over the 1st set of data that I needed.
This Link had a similar question but I'm either too dumb to figure out the formatting properly or I'm trying to import differently formatted data.
I'm hoping someone smarter than me will be able to figure out what I'm doing incorrectly.

Answers (2)

C.J. Harris
C.J. Harris on 6 Jul 2017
Try this:
[NUMERIC, TXT, RAW] = xlsread('My_Spreadsheet_Name');
You'll find the timestamps in both the TXT and RAW outputs. If you call xlsread the way you are, then you'll just get the numeric data.
  2 Comments
Walter Roberson
Walter Roberson on 7 Jul 2017
time_col = raw(:,1)
num_cols = cell2mat( raw(:,2:end) );
Now you can convert time_col with datenum() or (better) datetime()

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Peter Perkins
Peter Perkins on 7 Jul 2017
The best way to do this in a recent version of MATLAB is to use readtable, and create datetimes. This will free you from all the issues of converting excel serial dates.
  4 Comments
Walter Roberson
Walter Roberson on 11 Jul 2017
readtable is documented to interpret format strings the same way as textscan, and unless it has recently changed, textscan %D format specifiers cannot handle embedded spaces.
Ah.... testing now, I see that a '%{M/d/yy hh:mm aa}D' format spec can work for textscan, but only if whitespace has been set to exclude spaces.

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