| Answer: |
You could simply write your own sort algorithm (like a bubble
sort) and encapsulate it in a function, however there's another way that's
faster, while remaining very flexible. The key is using the JScript
array's highly efficient sort method. Since VBScript and JScript arrays
aren't directly interchangeable, we have to incur some overhead passing
them back and forth. But the overhead is usually worth it.
First we
define a JScript function that accepts a VBArray (a safeArray type),
changes it to a JScript array and sorts it:
<script language=JScript
runat=server>
function
SortVBArray(arrVBArray)
{
return
arrVBArray.toArray().sort().join('\b');
}
</script> |
That's all there is to, it but here's the breakdown of the one line
of code:
return Tells the function to return whatever
comes to the right of it as the output of the
function.
arrVBArray.toArray() Calls the
toArray() method of the VBArray to convert it to a JScript
array (this method is only available in
JScript).
.sort() Since the expression to the left of
this code evaluates to a Jscript array, we can now call the
sort() method of it, to perform a case-sensitive ascending
sort.
.join('\b'); This now joins the JScript array
into a delimited string. The '\b' is a special non-printable character
that is used as the delimiter because it will (almost) never appear in a
string unlike other potential delmiters such as the comma. This is how it
will be passed back to VBScript.
Next you need a VBScript function
to "finish off" what this function couldn't do in JScript, convert the
output to a VBScript array. It looks like this:
<%
Function
SortArray(arrInput)
SortArray
= Split(SortVBArray(arrInput),
Chr(8))
End
Function
%> |
Again only one line, this function uses the VBScript
Split function to reconstitue the VBArray, now in sorted
form. If you just wanted a sorted delimited string, you could call the
SortVBArray() function directly.
The performance of
this method is very good. Comparing executing time with a VBScript
implementation of a bubble sort (shown below) gave the following
results:
Array Size: 11 Items
SortArray: < 10ms
VB Bubble
Sort: <10ms
Array Size: 211 Items
SortArray: 10ms
VB
Bubble Sort: 160ms
Array Size: 1417 Items
SortArray: 30ms
(!)
VB Bubble Sort: 7090ms
The larger the array, the more the
savings with the .sort method. At 1417 items, it proves to be
well over 200 times faster than even a very well implemented VB
bubble sort!
VB bubble sort code:
<%
for i =
UBound(arrShort) - 1 To 0 Step -1
for j=
0 to i
if
arrShort(j)>arrShort(j+1)
then
temp=arrShort(j+1)
arrShort(j+1)=arrShort(j)
arrShort(j)=temp
end
if
next
next
%> |
Happy Programming!
|
