function S = datestr(D,varargin)

%DATESTR Character vector representation of date.

%   S = DATESTR(V) converts one or more date vectors V to text. S is a

%   character vector or character array with M rows, where M is the number

%   of rows in V. Input V must be an M-by-6 matrix containing M full

%   (six-element) date vectors. Each element of V must be a positive

%   double-precision number. 

%

%   S = DATESTR(N) converts one or more serial date numbers N to text. S

%   has M rows, where M is the number of rows in N. Input argument N can be

%   a scalar, vector, or multidimensional array of positive

%   double-precision numbers.

%

%   S = DATESTR(D, F) converts one or more dates into text using the format

%   F. Input argument F is a format number, character vector, or string

%   scalar that determines the format of the date character vector output.

%   D is one or more date vectors, serial date numbers, or a character

%   array or string array representing dates. Valid values for F are given

%   in Table 1, below. Input F may also contain a free-form date format

%   consisting of format tokens as shown in Table 2, below.

%

%   Dates in a text format using 2-character years are interpreted to be

%   within the 100 years centered around the current year.

%

%   S = DATESTR(S1, F, P) converts one or more dates into text using format

%   F. S is a character array using format F and pivot year P as the

%   starting year of the 100-year range in which a two-character year

%   resides. The default pivot year is the current year minus 50 years. F =

%   -1 uses the default format.

%

%   S = DATESTR(...,'local') returns S in a localized format. The default

%   (which can be called with 'en_US') is US English. This argument must

%   come last in the argument sequence.

%

%   Note:  The vectorized calling syntax can offer significant performance

%   improvement for large arrays.

%

%   Table 1: Standard MATLAB Date format definitions

%

%   Number           Format                   Example

%   ===========================================================================

%      0             'dd-mmm-yyyy HH:MM:SS'   01-Mar-2000 15:45:17 

%      1             'dd-mmm-yyyy'            01-Mar-2000  

%      2             'mm/dd/yy'               03/01/00     

%      3             'mmm'                    Mar          

%      4             'm'                      M            

%      5             'mm'                     03            

%      6             'mm/dd'                  03/01        

%      7             'dd'                     01            

%      8             'ddd'                    Wed          

%      9             'd'                      W            

%     10             'yyyy'                   2000         

%     11             'yy'                     00           

%     12             'mmmyy'                  Mar00        

%     13             'HH:MM:SS'               15:45:17     

%     14             'HH:MM:SS PM'             3:45:17 PM  

%     15             'HH:MM'                  15:45        

%     16             'HH:MM PM'                3:45 PM     

%     17             'QQ-YY'                  Q1-96        

%     18             'QQ'                     Q1           

%     19             'dd/mm'                  01/03        

%     20             'dd/mm/yy'               01/03/00     

%     21             'mmm.dd,yyyy HH:MM:SS'   Mar.01,2000 15:45:17 

%     22             'mmm.dd,yyyy'            Mar.01,2000  

%     23             'mm/dd/yyyy'             03/01/2000 

%     24             'dd/mm/yyyy'             01/03/2000 

%     25             'yy/mm/dd'               00/03/01 

%     26             'yyyy/mm/dd'             2000/03/01 

%     27             'QQ-YYYY'                Q1-1996        

%     28             'mmmyyyy'                Mar2000        

%     29 (ISO 8601)  'yyyy-mm-dd'             2000-03-01

%     30 (ISO 8601)  'yyyymmddTHHMMSS'        20000301T154517 

%     31             'yyyy-mm-dd HH:MM:SS'    2000-03-01 15:45:17 

%

%   Table 2: Date format symbolic identifiers (Examples are in US English)

%   

%   Symbol  Interpretation of format symbol

%   ===========================================================================

%   yyyy    full year, e.g. 1990, 2000, 2002

%   yy      partial year, e.g. 90, 00, 02

%   mmmm    full name of the month, according to the calendar locale, e.g.

%           "March", "April". 

%   mmm     first three letters of the month, according to the calendar 

%           locale, e.g. "Mar", "Apr". 

%   mm      numeric month of year, padded with leading zeros, e.g. ../03/..

%           or ../12/.. 

%   m       capitalized first letter of the month, according to the

%           calendar locale; for backwards compatibility. 

%   dddd    full name of the weekday, according to the calendar locale, e.g.

%           "Monday", "Tuesday". 

%   ddd     first three letters of the weekday, according to the calendar

%           locale, e.g. "Mon", "Tue". 

%   dd      numeric day of the month, padded with leading zeros, e.g. 

%           05/../.. or 20/../.. 

%   d       capitalized first letter of the weekday; for backwards 

%           compatibility

%   QQ      quarter of year, e.g. Q2

%   HH      hour of the day, according to the time format. In case the time

%           format AM | PM is set, HH does not pad with leading zeros. In 

%           case AM | PM is not set, display the hour of the day, padded 

%           with leading zeros. e.g 10:20 PM, which is equivalent to 22:20; 

%           9:00 AM, which is equivalent to 09:00.

%   MM      minutes of the hour, padded with leading zeros, e.g. 10:15, 

%           10:05, 10:05 AM.

%   SS      second of the minute, padded with leading zeros, e.g. 10:15:30,

%           10:05:30, 10:05:30 AM. 

%   FFF     milliseconds field, padded with leading zeros, e.g.

%           10:15:30.015.

%   PM      AM or PM

%

%   Examples:

%	DATESTR(now) returns '24-Jan-2003 11:58:15' for that particular date,

%	on an US English locale DATESTR(now,2) returns 01/24/03, the same as

%	for DATESTR(now,'mm/dd/yy') DATESTR(now,'dd.mm.yyyy') returns

%	24.01.2003 To convert a non-standard date form into a standard MATLAB

%	dateform, first convert the non-standard date form to a date number,

%	using DATENUM, for example, 

%	DATESTR(DATENUM('24.01.2003','dd.mm.yyyy'),2) returns 01/24/03.

%

%	See also DATE, DATENUM, DATEVEC, DATETICK.

%	Copyright 1984-2019 The MathWorks, Inc.

%==============================================================================

import matlab.internal.datatypes.stringToLegacyText

% handle input arguments

narginchk(1,4); 

D = stringToLegacyText(D); 

last = nargin - 1; 

islocal = 0; 

if last > 0 && (ischar(varargin{end}) || isstring(varargin{end})) 

    if strcmpi(varargin{end}, 'local')

        islocal = 1;

        last = last - 1;

    elseif strcmpi(varargin{end},'en_us')

        islocal = 0;

        last = last - 1;

    end

end 

if last > 2 

    % Force narginchk to error

    narginchk(1,2);

elseif last >= 1 

    dateform = stringToLegacyText(varargin{1}); 

    if last == 2 

        pivotyear =  varargin{2};

    end 

end 

isdatestr = ~isnumeric(D); 

if last > 0 

    if ~ischar(dateform) 

        % lookup date form string on index

        dateformstr = getdateform(dateform); 

    else

        dateformstr = dateform;

    end 

else

    dateformstr = '';

end 

if last == 2 && ischar(pivotyear) 

    error(message('MATLAB:datestr:InputClass'));

end 

% Convert character vectors and clock vectors to date numbers.

try 

    if isdatestr || (size(D,2)==6 && all(all(D(:,1:5)==fix(D(:,1:5)))) &&... 

        all(abs(sum(D,2)-2000)<500))  

        if last <= 1 || ~isdatestr  %not a datestring or no pivot year. 

            dtnumber = datenum(D); 

        else %datestring and pivot year were passed in.

            dtnumber = datenum(D,pivotyear);

        end 

    else %datenum was passed in 

        dtnumber = D; 

    end 

catch exception 

    error(message('MATLAB:datestr:ConvertToDateNumber', exception.message));

end 

% Determine format if none specified.  If all the times are zero,

% display using date only.  If all dates are all zero display time only.

% Otherwise display both time and date.

dtnumber = dtnumber(:); 

if (last < 1) || (isnumeric(dateform) && (dateform == -1)) 

   if all(floor(dtnumber)==dtnumber)

      dateformstr = getdateform(1);

   elseif all(floor(dtnumber)==0)

      dateformstr = getdateform(16);

   else

      dateformstr = getdateform(0);

   end

end  

S = dateformverify(dtnumber, dateformstr, islocal);