How can I convert a cell array of "random dates in the year" into time in year?

For ex: My input vector has random dates like 1993-4-1,1993-4-28 etc.Output should be 1993.000,1993.0039,1993.0078.I have used different functions (datevector, datenum etc). But they convert the date either to date numbers (730990) or yr month day format; not in the above output form. Btw I have to extract the input array from a .mat file. Thanks...

Answer 1

[Star Strider]

One possibility:

datestrs = {'1993-4-1'; '1993-4-28'};                               % Date String Cell Array
dnvct = datenum(datestrs, 'yyyy-mm-dd');                            % Convert To Date Numbers
dateyr = str2num(datestrs{1}(1:4));                                 % Get Year (Numeric)
range_yr_dn = datenum([dateyr 1 1 0 0 0; dateyr 12 31 23 59 59]);   % Start, End Of Year
range_yr_dn_diff = diff(range_yr_dn);                               % Year Range
year_fraction = (dnvct - range_yr_dn(1))./range_yr_dn_diff;         % Year Fraction For Each Input Date
Result = [repmat(dateyr, size(year_fraction,1), 1) + year_fraction] % Year Fraction In Desired Format

Result =

         1993.2
         1993.3

[Mushfika Baishakhi Upama]

it worked..many thanks :)

[Star Strider]

My pleasure!

Answer 2

[Matt J]

Here's a way using datetime,

    >> yourDates=datetime({ '1993-4-1','1993-4-28'},'InputFormat','yyyy-M-d')

    yourDates = 

       01-Apr-1993   28-Apr-1993

>> doy=day(yourDates,'dayofyear');
>> [Y,M,D]=ymd(yourDates); M(:)=12; D(:)=31;
>> doyDec31=day(datetime(Y,M,D),'dayofyear');

>> result=Y+doy/doyDec31;

Answer 3

[Stephen23]

One easy way would be to use my FEX submission num2date8601, which returns date strings whose format are controlled by tokens. One option is to provide a decimal fraction of any date/time unit. Here is an example with four decimal places of the calendar year:

>> C = {'1993-4-1'; '1993-4-28'};
>> arrayfun(@(n)str2double(datestr8601(n,'y4')),datenum(C))
ans =
                 1993.2465
                 1993.3205