-Literal- wrote:

Bump

-Literal- wrote:

Bump

-Literal- wrote:

Bump

Jonathan50 wrote:

15-MinuteGaming wrote:

However, it has the limitation that lists must be the exact same size…

That can be done by storing the items consecutively in a list and keeping the index (into the Scratch list) of the first item, which serves as a pointer, and then to access an item of the array add the index to the pointer. (Then you can make as many arrays as you like, but if you want to reuse space taken by arrays no longer needed, you would have to delete arrays once you're finished with them and change the constructor to find a free space of adequate length. The alternative is to use linked lists, which don't store their items one after the other; this makes ITEM slow but adding items at known positions becomes fast, but you still need to keep track of what's used and what isn't if you don't want to waste memory. If Scratch had first class lists then the browser would automatically reuse space taken by lists no longer needed, which is what most decent programming languages do.)

15-MinuteGaming wrote:

Also, with linked lists, each “list” must be the exact same size. If they do not need to be, please tell me how.

define locate list (x)
// gets the position of list x
set [j v] to [1] // the first item of a list holds its length
repeat ((x)-(1))
change [j v] by (item (j) of [Lists v] :: list)
end

define change length of (x) by (n)
// changes the length of list x
locate list (x)
set [k v] to ((item (j) of [Lists v] :: list)+(n)) // k holds the new length
replace item (j) of [Lists v] with (k)

define get item (x) (y)
// x selects the list, y selects the item
locate list (x)
set [item v] to (item ((j)+(y)) of [Lists v] :: list)

define add item (x) [item]
change length of (x) by (1)
insert (item) at ((j)+(k)) of [Lists v] // add the item

define delete item (x) (y)
change length of (x) by (-1)
delete ((j)+(y)) of [list v] // delete the item

define insert [item] at (x) (y)
change length of (x) by (1)
insert (item) at ((j)+(y)) of [Lists v] // insert the item

define replace (x) (y) with [item]
locate list (x)
replace item ((j)+(y)) of [Lists v] with (item) // replace the item

Scratch-Coding wrote:

This is a duplicate of https://scratch.mit.edu/discuss/topic/356259

15-MinuteGaming wrote:

The link is a 403 error.

WindOctahedron wrote:

space_elephant wrote:

WindOctahedron wrote:

With variables, it has already been done by other users.
Unfortunately, lists aren't first class* in Scratch. However, Snap! does have first class data.
*This means that lists can't contain lists.

Variables only work in 2.0.

But it's still easy to do it in 3.0.

define create variable (name)
add (name :: custom arg) to [names v]
add (0) to [values v]
define set (name) to (value)
replace item (item # of (name :: custom arg) in [names v] :: list) of [values v] with (value :: custom arg)
define change (name) by (value)
replace item (item # of (name :: custom arg) in [names v] :: list) of [values v] with ((name :: custom arg)+(value :: custom arg))
define delete (name)
delete (item # of (name :: custom arg) in [names v] :: list) of [values v]
delete (item # of (name :: custom arg) in [names v] :: list) of [names v]

Mr_PenguinAlex wrote:

Can't you just make the list on your own?

-Literal- wrote:

Bump

ScratchCatHELLO wrote:

Bump (I think it's allowed, it's been longer than 24 hours)