How do I import a timestamp from Excel/csv?
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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.
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回答 (2 件)
C.J. Harris
2017 年 7 月 6 日
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.
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Walter Roberson
2017 年 7 月 7 日
time_col = raw(:,1)
num_cols = cell2mat( raw(:,2:end) );
Now you can convert time_col with datenum() or (better) datetime()
Peter Perkins
2017 年 7 月 7 日
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 件のコメント
Peter Perkins
2017 年 7 月 11 日
For a CSV, you can also specify the 'Format' parameter in the call to readtable, with something like %{'M/d/yy h:mm a'}D for that field.
Or quick and dirty: t.Date.Year = t.Date.Year + 2000
Walter Roberson
2017 年 7 月 11 日
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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