function dtstrarray = formatdate(dtvector,formatstr,islocal)

%   FORMATDATE casts date vector into a specified date format

%   DATESTRING = FORMATDATE(DATEVECTOR, FORMATSTRING) turns the date

%   vector into text representing the date, according to the user's date

%   format template.

%

%   INPUT PARAMETERS:

%   DATEVECTOR: 1 x m double array, containing standard MATLAB date vector.

%   FORMATSTRING: char vector containing a user specified date format. See NOTE 1.

%

%   RETURN PARAMETERS:

%   DATESTRING: char vector, containing date and, optionally, time formated

%               as per user specified format.

%

%   EXAMPLES:

%   The date vector [2002 10 01 16 8] reformed as text representing date and time,

%   using a user format, 'dd-mm-yyyy HH:MM', will display as 

%   01-10-2002 16:08 .

%   

%   NOTE 1: The format specifier allows free-style date format, within the

%   following limits - 

%   ddd  => day is formatted as abbreviated name of weekday

%   dd   => day is formatted as two digit day of month

%   d    => day is formatted as first letter of name of weekday

%   mmm  => month is formatted as three letter abbreviation of name of month

%   mm   => month is formatted as two digit month of year

%   m    => month is formatted as one or two digit month of year

%   yyyy => year is formatted as four digit year

%   yy   => year is formatted as two digit year

%   HH   => hour is formatted as two digit hour of the day

%   MM   => minute is formatted as two digit minute of the hour

%   SS   => second is formatted as two digit second of the minute

%   The user may use any separator and other delimiters of his liking, but

%   must confine himself to the above format tokens regarding day, month,

%   year, hour, minute and second.

% 

%   

%------------------------------------------------------------------------------

% Copyright 2003-2019 The MathWorks, Inc.

if isempty(dtvector) || isempty(formatstr) 

    dtstrarray = '';

    return;

else 

    dtstr = formatstr; 

end 

showAmPm = [strfind(lower(dtstr), 'am'), strfind(lower(dtstr), 'pm')]; 

wrtAmPm = numel(showAmPm); 

% Canonicalize and error-check dtstr by converting it to ICU format.

dtstr = matlab.internal.datetime.cnv2icudf(dtstr,false); 

% To assist with formatting, use 'D' and 'S' for day and second, respectively,

% so as not to confuse the 'd' for day with '%d' and the 's' for second with

% '%s' when building the conversion character vector. Because millisecond is

% already 'S', replace that with 'F' first. None of these are "unused" chars, so

% we're not stepping on anything else.

dtstr = strrep(dtstr, 'S', 'F'); 

dtstr = strrep(dtstr, 'd', 'D'); 

dtstr = strrep(dtstr, 's', 'S'); 

% Use 'H' for all hour formats, this function looks for AM/PM to decide if

% it should display 24-hour or 12-hour (unlike ICU).

dtstr = strrep(dtstr, 'h', 'H'); 

showYr   = strfind(dtstr,'y'); wrtYr   = numel(showYr); 

showMo   = strfind(dtstr,'M'); wrtMo   = numel(showMo); 

showNday = strfind(dtstr,'D'); wrtNDay = numel(showNday); % ICU's 'd' 

showWday = strfind(dtstr,'E'); wrtWDay = numel(showWday); % ICU's 'e' 

showHr   = strfind(dtstr,'H'); wrtHr   = numel(showHr); 

showMin  = strfind(dtstr,'m'); wrtMin  = numel(showMin); 

showSec  = strfind(dtstr,'S'); wrtSec  = numel(showSec);  % ICU's 's' 

showMsec = strfind(dtstr,'F'); wrtMsec = numel(showMsec); % ICU's 'S' 

showQrt  = strfind(dtstr,'Q'); wrtQrt  = numel(showQrt); 

% Format day.

if wrtNDay > 0 

    dtstr = strrep(dtstr, 'DD', '%02d'); 

    day = abs(dtvector(:,3)); 

    showNday = showNday(1); 

else

    day = [];

end 

% Format weekday.

if wrtWDay > 0 

    if islocal

        locale = 'local';

    else

        locale = 'en_us';

    end

    [~, dayOfWeek] = weekday(datenum(dtvector), 'long', locale);

    switch wrtWDay

        case 4  % long weeday names (e.g., 'Monday')

            dtstr = strrep(dtstr, 'EEEE', '%s');

        case 3  % short weekday names (e.g., 'Mon')

            dtstr = strrep(dtstr, 'EEE', '%s');

            dayOfWeek = dayOfWeek(:, 1:3);

        case 1  % 1-letter weekday names (e.g., 'M')

            dtstr = strrep(dtstr, 'E', '%s');

            dayOfWeek = dayOfWeek(:, 1);

        otherwise % cases where a literal E was misinterpreted

            error(message('MATLAB:formatdate:dayFormat', formatstr));

    end

    showWday = showWday(1);

else 

    dayOfWeek = []; 

end 

% Format year.

% Calculating year may truncate the first element of the datevector to two

% digits, thus it must be done after any weekday calculations.

if wrtYr > 0 

    if wrtYr == 4 

            dtstr = strrep(dtstr,'yyyy','%.4d'); 

    else % wrtYr == 2

            dtstr = strrep(dtstr,'yy','%02d');

            dtvector(:,1) = mod(abs(dtvector(:,1)),100);

    end 

	year = mod(dtvector(:,1),10000); 

    showYr = showYr(1); 

else

    year = [];

end 

% Format quarter.

% This must happen after wrtNDay and wrtWDay are set.

if wrtQrt > 0 

    dtstr = strrep(dtstr,'QQQ', 'Q%1d');

	qrt = floor((dtvector(:,2)-1)/3)+1;

    showQrt = showQrt(1);

else 

    qrt = []; 

end 

% Format month.

if wrtMo > 0 

    switch wrtMo 

        case 4     %long month names 

            if islocal

                month = getmonthnamesmx('longloc');

            else

                month = {'January';'February';'March';'April';'May'; ...

                         'June';'July';'August';'September';'October'; ...

                         'November';'December'};

            end

            monthfmt = '%s';

            dtstr = strrep(dtstr,'MMMM',monthfmt);

            month = char(month(dtvector(:,2)));

        case 3     % short month names 

            if islocal 

                month = getmonthnamesmx('shortloc');

            else 

                month = {'Jan';'Feb';'Mar';'Apr';'May';'Jun';'Jul';'Aug';'Sep';'Oct';'Nov';'Dec'}; 

            end 

            monthfmt = '%s'; 

            dtstr = strrep(dtstr,'MMM',monthfmt); 

            month = char(strrep(month(dtvector(:,2)), '.', '')); %remove period 

        case 2    % two-digit month number

            dtstr = strrep(dtstr,'MM','%02d');

            month = abs(dtvector(:,2));

        otherwise % 1-letter month names

            if islocal

                month = getmonthnamesmx('shortloc');

            else

                month = {'J';'F';'M';'A';'M';'J';'J';'A';'S';'O';'N';'D'};

            end

            dtstr = strrep(dtstr,'M','%.1s');

            month = char(month(dtvector(:,2)));

    end 

    showMo = showMo(1); 

else

    month = [];

end 

% Format hour.

h = dtvector(:,4); 

if wrtHr > 0 

    if wrtAmPm > 0 

        fmt = '%2d';

        dtvector(:,4) = mod(h-1,12) + 1; % replace hour column with 12h format.

    else 

        fmt = '%02d'; 

    end 

    dtstr = strrep(dtstr,'HH',fmt); 

    hour = dtvector(:,4); 

    showHr = showHr(1); 

else

    hour = [];

end 

% Format AM/PM.

if wrtAmPm > 0 

    if islocal

        amPmVals = getampmtokensmx;

    else

        amPmVals = {'AM', 'PM'};

    end

    dtstr = strrep(dtstr, 'a', '%s');

    amPm(h < 12) = amPmVals(1);

    amPm(h >= 12) = amPmVals(2);

    amPm = char(amPm);

else 

    amPm = []; 

end 

% Format minute.

if wrtMin > 0 

    dtstr = strrep(dtstr,'mm','%02d'); 

	minute = dtvector(:,5); 

    showMin = showMin(1); 

else

    minute = [];

end 

% Format second.

if wrtSec > 0 

    dtstr = strrep(dtstr,'SS','%02d'); 

	second = floor(dtvector(:,6)); 

    showSec = showSec(1); 

else

    second = [];

end 

% Format millisecond.

if wrtMsec > 0 

    dtstr = strrep(dtstr,'FFF','%03d');

	millisecond = floor(1000*(dtvector(:,6) - floor(dtvector(:,6))));

    showMsec = showMsec(1);

else 

    millisecond = []; 

end 

% build date-time array to print

dtorder = [showYr, showQrt, showMo, showNday, showWday, ... 

           showAmPm, showHr, showMin, showSec, showMsec]; 

dtarray = {year, qrt, month, day, dayOfWeek, ... 

           amPm, hour, minute, second, millisecond}; 

dtarray = dtarray([wrtYr, wrtQrt, wrtMo, wrtNDay, wrtWDay, ... 

                   wrtAmPm, wrtHr, wrtMin, wrtSec, wrtMsec] > 0); 

% sort date vector in the order of the time format fields

[~, dtorder] = sort(dtorder); 

% print date vector using conversion character vector

dtarray = dtarray(dtorder); 

nrows = size(dtvector,1); 

if nrows == 1 

    %optimize if only one member

    dtstrarray = sprintf(dtstr, dtarray{:}); 

else

    dtstrarray = cell(nrows,1);

    numeldtarray = length(dtarray);

    thisdate = cell(1,numeldtarray);

    for i = 1:nrows

        for j = 1:numeldtarray

            % take horzontal slice through cells

            thisdate{j} = dtarray{j}(i,:);

        end

        dtstrarray{i} = sprintf(dtstr, thisdate{:});

    end

end