Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations wOOdy-Soft on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

Null?

Status
Not open for further replies.

rmc

Programmer
Feb 1, 2001
11
GB
I'm trying to find a short means of determining if an array contains no values (its storing the input from a multiple select box on a web page and my script works fine until nothing is selected in the list and the form submitted)

I think I need to use Null but can't figure out how? Any help much appreciated
 
You can ask if array(element) = null

This one always gets me, too -- if the above doesn't work, then try asking if it's

= empty

--or--

= ""

Ya know, though... probably the most reliable way is to initialize all the elements to some sentinel value, and then you know what you are looking for. For example, if you had a 10 element array that you would be stuffing with numbers, then I would probably just initialize them all to either 0 or 99 or something that I knew wouldn't normally be put into the array:

for i = 1 to 10
array(i) = 0
next

Then go about your business, and just check for 0 -- then you know for sure, and it will always work.

good luck! :)
Paul Prewett
 
Actually you can't use = null.

You need to use the function isNull

function ArrayContainsNull(ary) 'Returns boolean
for i = lbound(ary) to ubound(ary)
if isNull(ary(i)) then
'Short circuit if value is null
ArrayContainsNull = true
exit function
end if
next
ArrayContrainsNull = false
end function
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top