compare two dates

I know this is stupid, but is there an algorithim to determine if one date is less than the other? I mean like if one date is newer or older than the other? Thanks.

If "1234"<"4321" Notify "yay" Else Notify "darn!"
End

So, make sure your date string is sorted as: "yyyy-mm-dd"

Wait, its literally that simple?

if "2007-07-31" > "2007-07-30"
notify "Yup."
endif

Dang, thats easy, but is it reliable?

Nope, cos the year 2147483649 would appear as -1 so it would say that the 21st June 2147483641 was before 21st June 2001 (Bit like the millenium bug)

(This was a joke)

doubt this kind of coding would last that many years :P

basicly, they have a limit on how many numbers it can store, but if you do this for example...

[code]
curMonth="02"
curYear="2007"
curDate="21"

If curMonth < "03" and curYear < "2008" and curDate < "22"

print "yup."

else
print "nope."
end if

If your using strings, I really recommend casting them to integers:-

curMonth=Int("02")
curYear=Int("2007")
curDate=Int("21")

If curMonth < Int("03") And curYear < Int("2008") And curDate < Int("22")

Print "yup."

Else
Print "nope."
End If 
WaitKey 

Otherwise, the If expression returns 'nope', when infact, it should return 'yup'

Dabz

Nah, just compare strings like "2007-03-29" with "2008-03-31". How simple can it be? No milleniumbugs either:

If "1234567890123456789" > "123456789012345678" Notify "yay" Else Notify "darn"
End

If Int("1234567890123456789") > Int("123456789012345678") Notify "yay" Else Notify "darn"
End

I would still cast it in the code, as thats my preference! :)

Dabz

And reintroduce the Bug. Why?

Int("1234567890123456789") = 2112454933

Sorry, miles away (On the phone @ the same time as posting the above)... When doing the date thing, I would cast it:-

curMonth=Int("02")
curYear=Int("2007")
curDate=Int("21")

If curMonth < Int("03") And curYear < Int("2008") And curDate < Int("22")

Print "yup."

Else
Print "nope."
End If 
WaitKey 

Sorry if I mangled it, but regarding comparing dates in the format described in Yahfree's post, not large integers! :D

Dabz

The code does not work because if you had something like 23-04-2005 it would return "nope" since it failed two of the test conditions (day and month) - although the target date is lot earlier than the tested one...

But I'm having a few doubts of the best method myself of doing this job...

I think this should work, if this is what you were asking for.

;uses mm-dd-yyyy format, passed as a string
Function CompareDates(date1$,date2$) ;returns 1 if date1 is less, 2 if date2 is less, 0 if they are equal
	m1 = Int(Mid(date1$,1,2))
	d1 = Int(Mid(date1$,4,2))
	y1 = Int(Mid(date1$,7,4))
	
	m2 = Int(Mid(date2$,1,2))
	d2 = Int(Mid(date2$,4,2))
	y2 = Int(Mid(date2$,7,4))
	
	If y1 = y2 And m1 = m2 And d1 = d2 Then Return 0
	
	If y1 < y2
		Return 1
	ElseIf y1 = y2 And m1 < m2
		Return 1
	ElseIf y1 = y2 And m1 = m2 And d1 < d2
		Return 1
	Else
		Return 2
	End If	
End Function