Create a Calender matrix

Discussion in 'Mac Programming' started by dukebound85, Jun 10, 2012.

  1. dukebound85 macrumors P6


    Jul 17, 2005
    5045 feet above sea level
    Hi all, I have a quick question. I have gridded data I am trying to manipulate and for the sake of existing code I have written (that had this type of index with the data embedded in the netcdf file) would like to create an auxillary matrix with the corresponding time

    For instance, I have 12,xxx indexes that correspond to each day between Jan 1, 1979 to Dec 31, 2011

    I would like to create a 4x12,xxx array that is of the following behavior

    (Record, Month, Day, Year) where each one is 12,xxx in length

    Record is the raw index value (1-12,xxx)
    Month is the coressponding month of the index value (ie 31 consecutive 1's for Janurary, 28 consecutive 2s for Feb, etc and repeats)
    Day is the corresponding day (1-28(31)) for the index
    Year is the corresponding year (365 consecutive 1979, then 365 1980s, etc)

    Is there an easy way to make this type of array? I would need to take into accoun the leap years and what not

    Thanks for any tips
  2. Ron C macrumors member

    Jul 18, 2008
    I wouldn't store that information, rather I'd compute it for a given index.

    I'd start by figuring out how to convert the index into the appropriate NSTimeInterval value, then I'd use the NSDate and NSDateComponents classes to help me figure out the information I'm looking for. Read the documentation for more information on these classes, particularly the "Date and Time Programming Guide" - it gives you the answer in a section titled "Converting between Dates and Date Components."
  3. chown33 macrumors 604

    Aug 9, 2009
    Sailing beyond the sunset
    1. Which language?

    2. The intended meaning of "12,xxx" is unclear (though it might be clearer if we knew which language). Do you mean "approximately 12 thousand (~12,000, ~12k, ~12e3)" since the number of days in your date range is approximately 12 thousand (12,053)? Or do you mean "twelve" and the ",xxx" has some additional meaning? Or do you mean something else?
  4. subsonix macrumors 68040

    Feb 2, 2008
    What language are you using? There are date functions available to do what you want without storing every date in an array.
  5. dukebound85, Jun 10, 2012
    Last edited: Jun 10, 2012

    dukebound85 thread starter macrumors P6


    Jul 17, 2005
    5045 feet above sea level
    I am creating the array in matlab. The 12,xxx is more explicitly 12,053 values

    here is how I initially approached the problem.

    %% Calender maker
    record = [1:1:12053];
    y79 = [1:1:365];
    y80 = [1:1:366];
    y81 = [1:1:365];
    y82 = [1:1:365];
    y83 = [1:1:365];
    y84 = [1:1:366];
    y85 = [1:1:365];
    y86 = [1:1:365];
    y87 = [1:1:365];
    y88 = [1:1:366];
    y89 = [1:1:365];
    y90 = [1:1:365];
    y91 = [1:1:365];
    y92 = [1:1:366];
    y93 = [1:1:365];
    y94 = [1:1:365];
    y95 = [1:1:365];
    y96 = [1:1:366];
    y97 = [1:1:365];
    y98 = [1:1:365];
    y99 = [1:1:365];
    y00 = [1:1:366];
    y01 = [1:1:365];
    y02 = [1:1:365];
    y03 = [1:1:365];
    y04 = [1:1:366];
    y05 = [1:1:365];
    y06 = [1:1:365];
    y07 = [1:1:365];
    y08 = [1:1:366];
    y09 = [1:1:365];
    y10 = [1:1:365];
    y11 = [1:1:365];
    day = [y79,y80,y81,y82,y83,y84,y85,y86,y87,y88,y89,y90,y91,y92...
    I have netcdf files with length of the record dimension and am trying to manipulate it via data so hence my complimentary matrix I am attempting to recreate if that makes sense

    Edit: Figured it out...even though my code to generate it is not the most elagant!

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