Re: ReadListBinary -- Is this a bug?
- To: mathgroup at smc.vnet.net
- Subject: [mg17961] Re: [mg17947] ReadListBinary -- Is this a bug?
- From: "Andrzej Kozlowski" <andrzej at tuins.ac.jp>
- Date: Mon, 7 Jun 1999 02:51:19 -0400
- Sender: owner-wri-mathgroup at wolfram.com
In[1]:=
<<Utilities`BinaryFiles`
In[2]:=
Attributes[ReadListBinary]
Out[2]=
{HoldRest}
This means ReadListBinary evaluates only its first argument. So you need to
use:
kk = 20;
data = ReadListBinary[stream,Byte,Evaluate[kk]];
Andrzej Kozlowski
Toyama International University
JAPAN
http://sigma.tuins.ac.jp
http://eri2.tuins.ac.jp
----------
>From: Virgil Stokes <virgil.stokes at neuro.ki.se>
To: mathgroup at smc.vnet.net
>To: mathgroup at smc.vnet.net
>Subject: [mg17961] [mg17947] ReadListBinary -- Is this a bug?
>Date: Sat, Jun 5, 1999, 3:56 PM
>
> The following Mathematica code when
> using Mathematica 3.0 produces unexpected results.
>
> <<Utilities`BinaryFiles`;
> Remove[data,stream];
>
> data = Table[n,{n,10,100}]
>
> stream = OpenWriteBinary["TestFile"]
>
> WriteBinary[stream,data,ByteConversion->Identity]
> WriteBinary[stream,data,ByteConversion->Identity]
> Close[stream];
>
> stream = OpenReadBinary["TestFile"];
> SetStreamPosition[stream,20];
> data = ReadListBinary[stream,Byte,20]
>
> StreamPosition[stream]
> SetStreamPosition[stream,0];
>
> kk = 20;
> data = ReadListBinary[stream,Byte,kk] (* why doesn't this work? *)
> data = ReadListBinary[stream,Byte,20] (* while this works as expected *)
> SetStreamPosition[stream,0];
> data = ReadListBinary[stream,Byte]
>
> Close[stream]
>
> What is puzzling is that the above ReadlListBinary[stream,Byte,kk]
> does not execute as I would expect. It seems that the number of instances
> parameter
> for the ReadListBinary can not be symbolic -- why?.
>
> -- Virgil
>
>