Re: Chained-functional notation examples?

Path	csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!newspump.sol.net!post2.nntp.sol.net!posts.news.twtelecom.net!nnrp3.twtelecom.net!not-for-mail
From	roby <roby.nowak@gmail.com>
Newsgroups	comp.soft-sys.math.mathematica
Subject	Re: Chained-functional notation examples?
Date	Fri, 9 May 2014 06:06:05 +0000 (UTC)
Sender	steve@smc.vnet.net
Approved	Steven M. Christensen <steve@smc.vnet.net>, Moderator
Message-ID	<lkhr8d$dvd$1@smc.vnet.net> (permalink)
References	<lk9vb6$66t$1@smc.vnet.net>
Lines	75
Organization	Time-Warner Telecom
NNTP-Posting-Date	09 May 2014 06:12:23 GMT
NNTP-Posting-Host	10cb54c9.news.twtelecom.net
X-Trace	DXC=LCEWHMR9idao6SgMaR>^JiC_A=>8kQj6m;[h;PUXBgbdW:Sk\@?4VCfEFiONJ7[GofFBhM3lljDGd
X-Complaints-To	abuse@twtelecom.net
Xref	csiph.com comp.soft-sys.math.mathematica:16927

Show key headers only | View raw

Am Dienstag, 6. Mai 2014 08:26:46 UTC+2 schrieb Unknown:
> I came to 'Mathematica' via Xahlee's criticism of the ad-hoc nature of
>
> unix-piping [functional notation].  He claims [& I believe him] that Mathematica has a better, more consistent notation.  But the facility of PRE, IN & POST-fix alternatives, seems bad.  You want ONE way of acieving the goal. More rules just increases mental load.
>
>
>
> A major benefit of functional [unix-piping] programming style, is that you
>
> don't need to remember the-full-journey: you just need to remember the previous stage's output. Nor do you need to remember several names: the previous output is just "it".  A superficial read through a recent article[s] here, about <collecting data from several servers, and agregating it, and sending the result to a master> seemed very interesting, and matches my ideas of using functional programming.  But I can't afford to invest in ANOTHER notation/syntax, without good prospect of productivety increase.
>
>
>
> Just as a test, how would Mathematica handle the following [or part of]
>
> little task:
>
>
>
> search all files in Dir=tree D |
>
>  which are less than N days-old |
>
>  and which contain string S1 |
>
>  and which contain string S2 .
>
>
>
> Actually, this seems not a good example, since it's biased towards the *nix
>
> file system's format/syntax.
>
>
>
> Try:
>
> Search in table of ListOfOpenFiles for lineS with path-P [field] |
>
>  which have same tty-field as line with path-P2 & program-M [field]
>
>
>
> This sounds like a data-base problem?
>
>
>
> Or is there a nice list of 'such' Mathematica examples?
>
>
>
>  Thanks,
>
>
>
> == John Grant.


Well, I think that postfixing by use of the Mathematica Postfix operator "//"
accompanied by use of Mathematica pure Function "&" with access to the last result =
by using Mathematica Slot "#" (argument to the pure Function)
mimics *nix piping best:

the following gets all files of "c:/temp" in all sub dirs
older than 200 days
containing at least one of the strings "str1", "str2" :


"c:/temp" //
FileNames["*", #, Infinity]& //
Select[#, DateDifference[FileDate[#], DateList[]] > 200 &]& //
Select[#, StringMatchQ[#, "*str1*"] || StringMatchQ[#, "*str2*"]&] &

Regards Robert

Back to comp.soft-sys.math.mathematica | Previous | Next — Previous in thread | Find similar

Thread

Chained-functional notation examples? Unknown <dog@gmail.com> - 2014-05-06 06:26 +0000
  Re: Chained-functional notation examples? Unknown <dog@gmail.com> - 2014-05-07 06:45 +0000
  Re: Chained-functional notation examples? roby <roby.nowak@gmail.com> - 2014-05-09 06:06 +0000

csiph-web