[Date Index]
[Thread Index]
[Author Index]
Re: Chained-functional notation examples?
*To*: mathgroup at smc.vnet.net
*Subject*: [mg132701] Re: Chained-functional notation examples?
*From*: roby <roby.nowak at gmail.com>
*Date*: Fri, 9 May 2014 02:05:27 -0400 (EDT)
*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com
*Delivered-to*: l-mathgroup@wolfram.com
*Delivered-to*: mathgroup-outx@smc.vnet.net
*Delivered-to*: mathgroup-newsendx@smc.vnet.net
*References*: <lk9vb6$66t$1@smc.vnet.net>
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
Prev by Date:
**Re: Chained-functional notation examples?**
Next by Date:
**Re: parametric and analytical geometry**
Previous by thread:
**Re: Chained-functional notation examples?**
Next by thread:
**Re: Chained-functional notation examples?**
| |