This tip comes from Rafeeq

I was in search of an array function like the one below for ASP (being so lazy!), but I couldn't find one... so I decided to create my own! This function reads a file line by line and stores each line a dynamic array. First two object varibles - fso (file system object) and ts (textfileobject) - are created.

Set fso = CreateObject("Scripting.FileSystemObject") Set ts = fso.OpenTextFile(filename, ForReading)

Then I declared an array using ReDim statement with the size set one.

reDim myarray(0)

Now as long as I read from the file, I change the size of the array dynamically without destroying the previous elements and copy the current line read to the current array element.

While not ts.AtEndOfStream i=i+1 Redim Preserve myarray(i) myarray(i)=ts.ReadLine Wend

The final statement returns the myarray object from function File(filename). Here's the entire source code listing:

<% ' ////////////////////////////////////////////////////////////////// ' // ' // This function is a replica of PHP's "array file(filename)" ' // ' // Author Rafeeq C E email:rafeeqce@myiris.com ' // Wrote on 14-10-2000 during ---- Project ' // ' // Example: myarray=file("c:\mysongs.list") ' // ' ////////////////////////////////////////////////////////////////// Function File(filename) Dim fso,ts, myarray Const ForReading = 1 Set fso = CreateObject("Scripting.FileSystemObject") Set ts = fso.OpenTextFile(filename, ForReading) reDim myarray(0) i=-1 While not ts.AtEndOfStream i=i+1 Redim Preserve myarray(i) myarray(i)=ts.ReadLine Wend ts.Close File=myarray End Function %>

Cool Na! If you've trouble using this code (not for commercial purpose) feel free to drop a line at rafeeqce@myiris.com! (For more information on using the FileSystemObject, see the following FAQ: What is the FileSystemObject? For more information on resizing arrays, be sure to visit the FAQ: How can I dynamically resize an array?)

Comment from Bill Wilkinson
For large text files the above script is going to have horrible performance, doing the ReDim Preserve on every line!

*SO* much better to do:

<% .. ReDim ar(1000) Count = -1 .. Do Until... Count = Count + 1 If Count > UBound(ar) Then ReDim Preserve ar(Count+1000) ar(Count) = theFile.readLine Loop ' optional, if you want array exactly right size ReDim Preserve ar(Count) %>

But ReDim Preserve on each line??? Each empty element of an array only eats up 16 bytes of memory, so if the file turned out to have only 1 line, we are only wasting 16,000 bytes of memory. And even then we only waste it long enough to run through the loop. We only have to do a ReDim Preserve -- which is a VERY expensive operation in terms of time it takes and memory it uses! -- once every 1,000 lines (plus once more at the very end). If you had 1,300 lines in your file, you just save 1,298 ReDim Preserve calls! A huge performance advantage!

Thanks for the comment, Bill! :-)

Happy Programming!

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