How to compare two dates?

Getting Started Newbie Questions
#1

Hello,

I have looked everywhere and I cannot find how to compare two dates. I want to see if one date is greater than another. Can I just assign a date to a variable and compare like if dt1 > dt2 then?

Thanks,

Warren

#2

yes, if you use the standard date format : YYYY-MM-DD

#3

As @nmichaud said, if your dates are in YYYY-MM-DD format or YYMMDD you can get away with comparing the strings numerically.  However the best way is to convert the Date (and possible time) into the standard Unix epoch-based time values (i.e. seconds since Jan 1, 1970 at midnight GMT).   This is what functions like os.time() return.  Once you have two date-times in their seconds value it’s simple math to compare them. 

Look at the os.date() and os.time() functions documentation.  There should be decent discussion there about how to covert a date to a time value.  You can also look through:

http://coronalabs.com/blog/2013/01/15/working-with-time-and-dates-in-corona/

Where we talk about dates and times in a tutorial.  The conversion function might be a bit overkill, but it should show you how to use string.match() to parse out the values from a string and get it into a time value.

Rob

#4

yes, if you use the standard date format : YYYY-MM-DD

#5

As @nmichaud said, if your dates are in YYYY-MM-DD format or YYMMDD you can get away with comparing the strings numerically.  However the best way is to convert the Date (and possible time) into the standard Unix epoch-based time values (i.e. seconds since Jan 1, 1970 at midnight GMT).   This is what functions like os.time() return.  Once you have two date-times in their seconds value it’s simple math to compare them. 

Look at the os.date() and os.time() functions documentation.  There should be decent discussion there about how to covert a date to a time value.  You can also look through:

http://coronalabs.com/blog/2013/01/15/working-with-time-and-dates-in-corona/

Where we talk about dates and times in a tutorial.  The conversion function might be a bit overkill, but it should show you how to use string.match() to parse out the values from a string and get it into a time value.

Rob