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MathGroup Archive 2002

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RE: ReadList of Data containing "nan"

  • To: mathgroup at smc.vnet.net
  • Subject: [mg32816] RE: [mg32798] ReadList of Data containing "nan"
  • From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
  • Date: Thu, 14 Feb 2002 01:43:33 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

> -----Original Message-----
> From:	Adalbert Hanssen [SMTP:hanssen at zeiss.de]
To: mathgroup at smc.vnet.net
> Sent:	Tuesday, February 12, 2002 12:24 PM
> To:	mathgroup at smc.vnet.net
> Subject:	[mg32798] ReadList of Data containing "nan"
> 
> Hi, MathGroup,
> 
> from a measuring instrument, I get an tab-delimited ASCII file of records,
> each consisting of five numbers.
> 
> Up to now, I used to read those records like this (I deliberately skip the
> first two lines):
> 
>        fil=OpenRead[fileName];
>        liste={};				(* start with an empty list
> *)
>        Read[fil,String];		(* skip the first and the   *)
>        str=Read[fil,String];		(* second line in the file  *)
>        While[(str=Read[fil,String])=!=EndOfFile
>             ,strstr=StringToStream[str];
>              zeile=ReadList[strstr, Real, WordSeparators->{"\t"}];
>              Close[strstr];
>              liste=Append[liste,zeile];
>             ];
>       Close[fil];
>       (* now liste contains all the data from the file *)
> 
> This works fine for me. Now I am getting results, which have lines, where
> one or more of the numbers in a line are "nan" because of an out-off-range
> condition of the measuring instrument. I want to read those lines
> nevertheless, but I want the "nan"-items be represented by Indeterminate
> in Mathematica.
> 
> Which is the best way to read all the data simultaneously converting the
> figures "nan" to Indeterminate in Mathematica?
> 
> 
> kind regards
> 
> Dipl.-Math. Adalbert Hanszen
> 
[Hartmut Wolf]  

Adalbert,

who knows? Consider this:

 
astring="1.\t2.\tnan\tnan\t5."

1.	2.	nan	nan	5.

strstr=StringToStream[astring];

(zeile=Block[{Times=Sequence,nan=Indeterminate},
        ReadList[strstr,Expression,
                 WordSeparators->{"\t"}]])//InputForm

{1., 2., Indeterminate, Indeterminate, 5.}

--
Hartmut



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