dates between two limits

Hi, I want to make a script between start_date to end_date with the following conditions

for example start_date = '20190131'

end_date ='20190205'

so what I want ,

start_date(1:4) must consist of 4 digits

start_date(5:6) should only take values ​​between 1 and 12

start_date(7:8) should only take values ​​between 1 and 31 and same thing for end_date

if my conditions are right it will run my program otherwise it will show me wrong date.

Answer 1

[YT]

I came up with 2 options:

OPTION 1

clear;
start_date = '20190131';
end_date  = '20191205';
myFormat = 'yyyyMMdd';

DateStrings = {start_date; end_date};
t = datetime(DateStrings,'InputFormat',myFormat);
if(~isnat(t))
    disp('Everything OK');
else
    disp(['Wrong string:  ' strjoin((DateStrings(isnat(t))),', ')]); 
end

Now option 1 works pretty good, but if you input a wrong day number, datetime will throw an error and it does not specify which of the strings (start_date / end_date) was wrong.

OPTION 2

It may seem a bit "spaghettified", but you have to wrap both the start and end date seperatly in a try/catch statement if you really want to let the user know which one of the dates was wrong.

clear;
start_date = '20190131';
end_date  = '20191205';
myFormat = 'yyyyMMdd';

try
    tStart = datetime(start_date,'InputFormat',myFormat);
catch
    error(['Unable to convert `' start_date '` to datetime using the format `' myFormat '`']);
end

try
    tEnd = datetime(end_date,'InputFormat',myFormat);
catch
    error(['Unable to convert `' end_date '` to datetime using the format `' myFormat '`']);
end

if (~isnat(tStart) && ~isnat(tEnd)) %check once more if dates are valid (yes this is necessary)
    disp('Dates are valid!');
else
    if(isnat(tStart))
        error(['Input `' start_date '` invalid datetime format. Correct format is `' myFormat '`.']);
    elseif(isnat(tEnd))
        error(['Input `' end_date '` invalid datetime format. Correct format is `' myFormat '`.']);  
    end
end