Splitting a timestamp in Matlab

Question

I have a file with a data value and timestamp that I am trying to split in Matlab. This is the format:

-18.151346    Mon Jan 28 11:33:08 2013

I am using the textscan function to try and split it.

data=textscan(fid,'%f%s%s%f%s%n','delimiter','space');

I am trying to split the timestamp into separate columns so that I can just use the time and not the date or year. I had a look at some previous questions which were very similar but for some reason I just can't get it to do what I want. My resulting cell array is in this format.

Column 1     Column 2   Column 3 
-18.151346   Mon       Jan 28 11:33:08 2013

I am completely new to Matlab so any help would be greatly appreciated. Thanks in advance.

Answer 1

1. You're using a 'space' string as a delimiter, which is illegal in textscan. Specify it as ' ' instead.
2. You want treat consecutive spaces as one, so you should also set the 'MultipleDelimsAsOne' flag to 1.

The correct syntax should be:

textscan( fid, '%f%s%s%s%s%n', 'delimiter', ' ', 'MultipleDelimsAsOne', 1);

Had you not tried to tinker with the delimiter option, this behavior would've been done properly by default, so just omit all options:

textscan( fid, '%f%s%s%s%s%n');

Also note that you need a flag for each item in the string that is surrounded by spaces. In other words, for a string like this:

-18.151346 Mon Jan 28 11:33:08 2013

the timestamp in string form will be stored in the 5th column of the resulting cell array.

Answer 2

To read the timestamp I'd use regexp.

The solution I'm gonna advise can be optimized, but it can help you at least as first try.

A = regexp(str,'[^\s]+','match');

This way you match all the regular expressions within your string. Then, you know that values and time are stored as element 1 and 5.

I made a short test with:

cell = {'-18.151346 Mon Jan 28 11:33:08 2013','19.33333 Tue Feb 29 10:12:23 2012'};

and this leads you to a cell A{1,2}.

Again, this procedure is perfectible, but you can use it as hint.