Date: Sep 6, 2013 10:13 AM
Author: Curious
Subject: Re: what to use when reshape is not good anymore?please some help

"Marinela Finta" wrote in message <l0bqi5$1th$1@newscl01ah.mathworks.com>...
> I am just starting to learn matlab and I would appreciate very much if you could help me...
>
> I am stuck with calculating the returns between some hours and for each day..
> For some date was going ok the following method:
> (now the price is between that hours)
> n=length(price);
> % The number if days
> %(79 is the number of observations within one day)
> ndays = n/79;
> price_d = reshape(price,79,ndays);
> %I take returns for each day
> returns_d = log(price_d(2:79,:))- log(price_d(1:78,:));
>
> However now I have another data where the number of observations are not anymore the same for each day..So in one day I have 79 in another 30,75 observations within a day.Therfore i CANNOT use anymore RESHAPE..:(


I'm not sure why you can't use RESHAPE.
What happens if you make 79 a variable and then
change it to 30, 75, or whatever based on how you
know that the number of observations change.
(Same for 78 in your above code.)

Also, it seems to me that you should do some error checking
to ensure that ndays is an integer (due to floating point arthmetic).
>

> How should I do in order to have sorted the observations(prices) according to each day? So to have similar thing as before: row with the prices and column with prices corresponding to each day..
> thank you for your time..
> Marinela
>