As an example, consider a list ["a", "b", "c"]. "a" is in the list. But the list ["a", "b"] is *not* in the list, as it is not an element of the list - all the elements of the list are strings, and ["a", "b"] is a list. However, ["a", "b", "c"] *does* contain ["a", "b"] as the latter occurs as a 'substring' (in the sense of the wikipedia links I posted).
On Wed, Jan 4, 2017 at 1:39 PM Mike Kerner <mikeker...@roadrunner.com> wrote: > WHAT? > There is some subtlety that I am missing, Ali. > > On Wed, Jan 4, 2017 at 5:22 AM, Ali Lloyd <ali.ll...@livecode.com> wrote: > > > Peter has pointed out that I am technically using the word 'subsequence' > in > > error, and should probably have used 'substring' instead! > > (cf https://en.wikipedia.org/wiki/Subsequence vs > > https://en.wikipedia.org/wiki/Substring) > > > > On Wed, Jan 4, 2017 at 10:16 AM Ali Lloyd <ali.ll...@livecode.com> > wrote: > > > > > 'contains' and 'is in' are implemented exactly the same in LiveCode > > > Script, so there shouldn't be any difference. However there is an > > > interesting subtlety that emerges when you consider what these two bits > > of > > > syntax should do, which explains why they are different in LCB. > > > > > > When we say 'A contains B' where A is some sort of sequence (ordered > > set), > > > then I would argue we really mean that B is a subsequence of A. On the > > > other hand I think the interpretation of 'is in' is the same as that of > > 'is > > > among the elements of'. > > > > > > Thus 'contains' is actually a relation between sequences and sequences, > > > whereas 'is in' is one between elements and sequences. This makes no > > > difference in LCS for strings because the type of the sequence is the > > same > > > as the type of the element, namely they are strings. However it does > mean > > > that the following two should be considered anomalous: > > > > > > 1) In LCS, 'is in' does not restrict the left hand side to a single > char > > > 2) In LCS, no string other than empty 'contains' empty > > > > > > Both of these anomalies are rectified in LCB. The situation becomes > > > clearer when using an LCB list, where <list> contains <string> is a > > syntax > > > error, and <listA> is in <listB> is only true if listA occurs as an > > > *element* of listB, rather than a subsequence. Moreover <list> contains > > [] > > > is always true. > > > > > > > > > tl;dr - there should be no performance difference between 'contains' > and > > > 'is in' in LCS. > > > > > > > > > On Tue, Jan 3, 2017 at 11:35 PM Bob Sneidar < > bobsnei...@iotecdigital.com > > > > > > wrote: > > > > > > I interact with copier interfaces quite a lot and the process of > backing > > > up the data involves going through various pages and typing what I see > > > there into a text file. I have always thought it would be great to > write > > an > > > app that can do it for me, but I have never been able to scrape > anything > > > more than the HTML text displayed on the page. > > > > > > I will have to look into ways to use Javascript to do it. If it > requires > > > already knowing what the values are though, I'm afraid I might meet > with > > > unsurpassable difficluty. > > > > > > Bob S > > > > > > > > > On Jan 3, 2017, at 15:02 , Mike Kerner <mikeker...@roadrunner.com< > > mailto: > > > mikeker...@roadrunner.com>> wrote: > > > > > > the short answer is "yes", but it can be more complicated as it may > > require > > > some javascript execution to pull the data from the server. It depends > > on > > > the site you are scraping. You can also (possibly) use a service that > > can > > > yank that for you. > > > > > > _______________________________________________ > > > use-livecode mailing list > > > use-livecode@lists.runrev.com > > > Please visit this url to subscribe, unsubscribe and manage your > > > subscription preferences: > > > http://lists.runrev.com/mailman/listinfo/use-livecode > > > > > > > > _______________________________________________ > > use-livecode mailing list > > use-livecode@lists.runrev.com > > Please visit this url to subscribe, unsubscribe and manage your > > subscription preferences: > > http://lists.runrev.com/mailman/listinfo/use-livecode > > > > > > -- > On the first day, God created the heavens and the Earth > On the second day, God created the oceans. > On the third day, God put the animals on hold for a few hours, > and did a little diving. > And God said, "This is good." > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your > subscription preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode > _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
