Checking if a Date is Valid in MATLAB - matlab

Question

So as to not mislead anyone, this is a HW problem that I am attempting to complete and need a little help with. The problem itself is pretty self-explanatory. I have to write a function where I input a string 'Month Day, Year' and have it tell me whether or not it's valid (true or false statements). I have it working for almost everything, except now it doesn't seem to recognize my constraints for possible days.
function[valid] = isValidDate(str)
[date, year] = strtok(str, ','); %Should give me the date and year
[~, year2] = strtok(year, ' ');
[month, day] = strtok(date, ' '); %Should give me month and the day
day = round(day);
if length(date) < 6
valid = false;
elseif month(1) == upper(month(1))
valid = true;
elseif length(date) >= 12
valid = false;
end
if year2 >= 0
valid = true;
else
valid = false;
end
leapyear = mod(year, 400) == 0 | (mod(year, 4) == 0 ~= mod(year, 100) == 0);
switch month
case {'September','April','June','November'}
day <= 30;
valid = true;
case {'February'}
if leapyear
day <= 29;
valid = true;
else
day <= 28;
valid = true;
end
case {'January', 'March', 'May', 'July', 'August', 'October', 'December'}
days <= 31;
valid = true;
otherwise
valid = false;
end
end
So basically
valid4 = isValidDate('December 29.9, -1005.7')
valid = false
Note: There will be no suffix after the day. My only issue now is that my function doesn't realize my constraints on days. it likes to think 'February 30, 2014' is possible

Answer 1

Code
function[valid] = isValidDate(str)
[date1, year1] = strtok(str, ','); %Should give me the date and year
[month1, day1] = strtok(date1, ' '); %Should give me month and the day
%// 1. Take care of bad month strings
all_months = {'January', 'February','March', 'April', 'May','June',...
'July', 'August', 'September','October','November' 'December'} ;
if ~ismember(cellstr(month1),all_months)
valid = false;
return;
end
%// 2. Take care of negative or fraction days
day1 = day1(isstrprop(day1,'digit')); %// Take care of suffixes after day string
num_day = str2double(day1);
if round(num_day)~=num_day || num_day<1
valid = false;
return;
end
%// 3. Take care of fraction or negative years
num_year = str2double(strtok(year1,','));
if round(num_year)~=num_year || num_year<0
valid = false;
return;
end
lpyr =mod(num_year, 400) == 0 | (mod(num_year, 4) == 0 ~= mod(num_year, 100) == 0);
switch month1
case {'September','April','June','November'}
if num_day > 30
valid = false;
return;
end
case {'February'}
if (lpyr && num_day > 29) | (~lpyr && num_day > 28)
valid = false;
return;
end
case {'January', 'March', 'May', 'July', 'August', 'October', 'December'}
if num_day > 31;
valid = false;
return;
end
end
valid = true; %// We made it through!
return;
If you would prefer a compact code -
function valid = isValidDate(str)
[date1, year1] = strtok(str, ','); %Should give me the date and year
[month1, day1] = strtok(date1, ' '); %Should give me month and the day
%// 1. Take care of bad month strings
all_months = {'January', 'February','March', 'April', 'May','June',...
'July', 'August', 'September','October','November' 'December'} ;
valid_month = ismember(cellstr(month1),all_months);
%// 2. Take care of negative or fraction days
day1 = day1(isstrprop(day1,'digit')); %// Take care of suffixes after day string
num_day = str2double(day1);
valid_day = round(num_day)==num_day && num_day>=1;
%// 3. Take care of fraction or negative years
num_year = str2double(strtok(year1,','));
valid_year = round(num_year)==num_year && num_year>=0;
%// 4. Take care of valid days based on leap year and days in a month limits
lpyr = mod(num_year, 400) == 0 | (mod(num_year, 4) == 0 ~= mod(num_year, 100) == 0);
valid_leapyear = true;
switch month1
case {'September','April','June','November'}
valid_leapyear = num_day<=30;
case {'February'}
valid_leapyear = ~((lpyr && num_day>29) || (~lpyr && num_day>28));
case {'January', 'March', 'May', 'July', 'August', 'October', 'December'}
valid_leapyear = num_day<=31;
end
valid = valid_year & valid_month & valid_day & valid_leapyear;
return;

Answer 2

I made some simple function, using the java interface in matlab. Hope it will be useful.
function [valid] = isValidDate(dateStr)
valid = true;
dateFormat = java.text.SimpleDateFormat('MMM dd, yyyy');
dateFormat.setLenient(false);
try
dateFormat.parse(dateStr);
valid = true;
catch err
valid = false;
end
end
Example:
isValidDate('December 21, 1934'); % gives 1
isValidDate('December 29.9, -1005.7'); % gives 0