find the number of seconds between two times

One time comes from a vector, date (which I only want the first date) and the other one is a string form.

time0 = datenum(date(1),'HH:MM:SS.FFF');
time1 = datenum('12:35:00','HH:MM:SS');
past_time1=etime(time1,time0);

but I get an error when I run this: Index exceeds matrix dimensions.

Error in etime (line 40)
t = 86400*(datenummx(t1(:,1:3)) - datenummx(t0(:,1:3))) + ...

Error in processdata (line 107)
past_time1=etime(time1,time0);

Why isn't this working?

date(1) contains the value '12:31:45.115'

Answer 1

[Adam]

date(1) cannot contain a full string. If date is that string then date(1) is just '1'. Alternatively if date is a cell array you want data{1} instead.

Also do not call your string 'date', you are obfuscating a builtin function which may also be the cause of your error if it is being called from inside another function.

[thestargazer]

I think I solved the problem with 'datevec'. date(1) contains a string with format hh:mm:ss.fff.