How big can a list get...

Scripting Forums AppleScript | Classic Mac OS
#1

…before invoking a -20013 error?
Is it a matter of items, or is it the number of individual characters in total?
TIA
Doug

#2

It would probably be number of items in the list. But I’m not sure what the limit is… Anyone else?

#3

Hi Doug,
I just did a couple of tests and couldn’t produce an error. The unscientific
test consisted of a repeat loop (20,000 times) which copied a four letter
word to the end of a list. I’ll attempt to push it until it errors but the script
takes quite some time to run, so it may take a while to hit the limit.
Do you have a script which is producing the error or are you just preparing
for it?
Rob J

#4

I think it depends on memory and if the text field that you are using uses the Text Edit Manager (which has a 32k limit. If you’re running it in the Script Editor then it’s the Script Editor’s memory and its text field limit. If from a script application then the script’s memory can be increased. Then, the variable can hold a lot. But, if you show your list like say in Dialog Director then its text field also has the 32k limit I think. One error you may get from the Script Editor is because the result window has a limit (probably 32k).

#5

I just ran the script for 70,000 iterations and still didn’t hit any limits. This created a list of 70,000 four letter words. FYI, my environment is OS 9.1, AppleScript 1.6 and Script Debugger 3.x.
Uncle! I give up!
Rob J
P.S. The four letter word was “word”. :stuck_out_tongue:

#6

Hi,
I got this from the AppleScript Language Guide. To speed up things use the ‘a reference to’ operator. For instance:

set the_list to {} 
set the_list_ref to a reference to the_list 
repeat 50000 times 
 copy "word" to end of the_list_ref 
end repeat 
display dialog ((the data length of the_list) as string) & " bytes."

Note: for really big list, as Rob says you need to copy or set to the end of the list instead of concatenating.

#7

Sorry about this, but, the last line uses Akua Sweets. I put that in so that the result window wouldn’t try to show the list.

#8

There may be ways to overcome those limits ( e.q. do not use those apps, writing and reading the long list to/from a file, chunk by chunk).

I am not sure what the physical limits are, but would be surprised if they would surpass RAM / disk space :wink:
Eelco Houwink