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
