How would YOU delete all blank lines from List Object?

[ratty]

I've done this a few ways now but none of them seems as concise as it should be. I had a good working method but it stopped working for some reason...

Anyway, having a list that's populated during runtime, how would you have all blank lines removed from it (assuming they interspersed among lines with text)?

[Popcorn]

This is tested and works fine:

Set the list to be base 0 indexed.
Make a counter.
Run a loop as many times as there are lines in the list.

* On loop
+ line at Counter1 is blank
- List: delete line at current value of Counter1
- Counter1: sub one

* On loop
- Counter1: add 1

[Nifflas]

Here's an alternative that doesn't need a counter, but needs to re-create the entire list (in other words, you may want to stick to Popcorn's solution)

Start out like in Popcorn's example:
0 based index list.
Run the loop as many times as there are lines in the list.

* On loop
+ line at 0 <> blank
- List: Add line [text of line 0]

* On loop
- List: Delete line 0

[macca02]

Well i would've thought it would be as simple as this:

Run a loop, with number of lines from the list as the number of iterations.

On Loop "delete"
+ ListLineText$("List", Loopindex("delete")) = ""
Delete line Loopindex("delete").


However, i just tried that and you have to run the loop a couple of times to get rid of all the lines....... anyone know why this is? logically to me it seems like it should work, but it doesn't?

EDIT: Workaround is adding in an action to restart the loop. effectively keeps going until all blank lines are deleted. Example MFA is included!

On Loop "delete"
+ ListLineText$("List", Loopindex("delete")) = ""
Delete line Loopindex("delete").
Start Loop "delete", for: numberOfLines(list).

EXAMPLE MFA

[Nifflas]

However, i just tried that and you have to run the loop a couple of times to get rid of all the lines....... anyone know why this is? logically to me it seems like it should work, but it doesn't?

It doesn't work because the line indexes changes every time you remove a line. If for example line 3 is blank, and it is removed, the next line you want to check will also be line number 3, not 4.

EDIT: Workaround is adding in an action to restart the loop. effectively keeps going until all blank lines are deleted. Example MFA is included!

That's not a good solution. For each non-blank line, you recurse and run the fastloop another List Nb Lines( "List" ) times. In your example, the fastloop is triggered 336 times. Both Popcorn's and my solutions runs the fastloop as many times as there are lines, no more.

[macca02]

It doesn't work because the line indexes changes every time you remove a line. If for example line 3 is blank, and it is removed, the next line you want to check will also be line number 3, not 4.
That's not a good solution. For each non-blank line, you recurse and run the fastloop another List Nb Lines( "List" ) times. In your example, the fastloop is triggered 336 times. Both Popcorn's and my solutions runs the fastloop as many times as there are lines, no more.

Well that makes alot of sense now!
Just tried the solutions you and popcorn made and as you mentioned they are much more efficient!

[ratty]

Macca02 found the same issue I did. Popcorn and Nifflas, awesome examples. That solves the repetition issue!

[AyreGuitar]

ratty - just come across a novel way to do this, based on a bug I just found in List object: simply save your list, reset and load it back - all blank lines will be removed!
Of course, if this really is a bug, then it may get fixed soon, so perhaps not a good idea to rely on it just yet:
http://community.clickteam.com/threads/81524-List-Object-txt-file-load-removing-blank-lines?p=598901#post598901