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Topic: Chained-functional notation examples?
Replies: 5   Last Post: May 9, 2014 2:07 AM

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hmichel@cox.net

Posts: 122
Registered: 1/29/05
Re: Chained-functional notation examples?
Posted: May 9, 2014 2:07 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

I think the dates would have to be rounded to Day then the AbsoluteTime
would be more comparable.

AbsoluteTime[DayRound[DateList[], All]] <
AbsoluteTime[DayRound[DayPlus[DateList[], 3], All]]

Issues may be file dates compared to current date time, rounding and
location (timezone) issues.

DayRound is New in version 9
Switch to Take[] goes all the back to v1. AbsoluteTime v2.

AbsoluteTime[Take[DateList[], 3]] <
AbsoluteTime[Take[DayPlus[DateList[], 3], 3]]

FileDate[] in the original suggestion by Daniel only goes back to v3.

To address the poster's original questions: I don't believe that
Mathematica has issues in filtering or using a water-fall like method. I
can't speak to if Mathematica optimizes such a process.

Hans
-----Original Message-----
From: Daniel Lichtblau [mailto:danl@wolfram.com]
Sent: Thursday, May 08, 2014 9:37 AM
To: Hans Michel; mathgroup@smc.vnet.net
Subject: Re: Chained-functional notation examples?


On 05/08/2014 09:20 AM, Hans Michel wrote:
> Daniel:
>
> Now What's the catch with Today?
>
> Today will only work in Wolfram Language (Mathematica v 10), which may
> be officially released Tomorrow?
>
> One can go on with a Who's on First theme. (Goes along with W|A
> baseball
> data)
>
> But currently the DateObject "Today" would have to be changed to
> something that would work in Mathematica 9 or below.
>
> Hans


Hans et al,

You are correct, I was using an unreleased version. Actually some good came
of it (I found a weakness in date comparisons that got addressed).
I'll leave modification for versions <=9 to others more adept at this sort
of thing. I never was much good with dates...

As for baseball,

http://www.redreporter.com/2012/2/13/2796324/hus-on-first-a-modernization

Daniel


> -----Original Message-----
> From: Daniel Lichtblau [mailto:danl@wolfram.com]
> Sent: Thursday, May 08, 2014 3:08 AM
> To: mathgroup@smc.vnet.net
> Subject: Re: Chained-functional notation examples?
>
>
> A query such as this might do what you have in mind. Here
> directoryname should be changed to whatever directory you want searched.
>
> Select[FileNames[("*uid*" | "*UID*"), directoryname, Infinity],
> ((StringMatchQ[DirectoryName[#] , "*egal*"] && Today <
> DayPlus[FileDate[#], 3]) &]
>
> Also there is a case sensitive switch if you want to allow strings with

e.g.
> "uID". If you want to allow that uid only in the name and not full
> string
>
> Daniel Lichtblau
> Wolfram Research
>
> -------------------
>
> On Tue, 06 May 2014 06:26:46 +0000, Unknown wrote:
>

> > 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.

>
> Here's a related real-live problem:
> list all files in Dir-tree:D |
> which are less-than daysOld:N |
> and contain "egal" in the FullPathName |
> and contain String:"uid" OR "UID"
>






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