anamaria

I would like to know if there is a list object that lets me find a given sequence of numbers in any list.

For example, if I have this list 0 0 0 3 0 4 2 1 1 1 3 3 2 6 5 0 0 then I would like to see if this sequence of numbers: 2 1 1 1 is in the list (which it is).

how-to-find-a-sequence-of-number-in-any-list

The regexp object is IMO best suited for that task.

I have to disagree on that one because it seems zl sub has a problem dealing with the spaces in the list. I've added a proof of concept below, even if you specify the list which I used on the regexp as an argument for zl (so with use of the quotes) it still doesn't detect the occurrence.

I unfortunately didn't try with anamaria's example :-)

You're right, but this looks like a bug for me, don't you think?

It seems so but I have a very hard time understanding what it is. At first I suspected something wrong but was under the impression that zl wasn't up to it. Now that you confirmed that this seems quite odd (a bug) I did a few other tests and well...

Be sure to use zlclear and 'mode sub' to re-init the zl object. But as you can see it seems unable to grok "2 1 1" which is really part of the list. But now comes the part I fail to understand: "1 1 3" is picked up without a problem.

Then I thought about sequence; '2 1 1' is the 7th number (the 2). The 6 (in 6 5 0) is the 14th yet that doesn't pose any problems either.

I agree this looks like a bug, but a very strange one, very hard to reproduce too so it seems.

It seems to be a general bug which can be described and reproduced like this:

Given a list containing a sequence 'a b b b' the sublist 'a b b' is not recognized.

The [zl sub] object also starts searching from the end of the last match so it will find one match when searching "1 1 1 2 3 4" for "1 1" at the first element rather than two, starting from the first 

I wrote a javascript that starts searching from every element rather than searching from the next element after a preceeding match is found. It can be used in this case effectively too although it doesn't explain the problem.

 in the MaxMSP library download if you like.

The [zl sub] object also starts searching from the end of the last match so it will find one match when searching "1 1 1 2 3 4" for "1 1" at the first element rather than two, starting from the first and second elements.

You can find the javascript here in the MaxMSP library download if you like.


No reaction from c74, maybe I should write a real bug report!

With some more testing I've noticed the following pattern.

List 'a b b b b b' -> 'a b b' is NOT found.

List 'a b b' -> 'a b b' is found.
List 'a b b b' -> 'a b b' is NOT found.
List 'a b b b b' -> 'a b b' is found.
List 'a b b b b b' -> 'a b b' is NOT found.

how to find a sequence of number in any list