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MathGroup Archive 2007

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Block[], OpenRead[], & /@

  • To: mathgroup at smc.vnet.net
  • Subject: [mg75862] Block[], OpenRead[], & /@
  • From: "Mary Beth Mulcahy" <mulcahy.marybeth at gmail.com>
  • Date: Sat, 12 May 2007 03:05:27 -0400 (EDT)

I am trying to write a more succint code to import multiple data files, but
I am having problems mapping the Block[] command with an OpenRead[]
command.  As my code is now, I read the files names from the parent
directory and then cut and past all the names into the OpenRead[] command
seen below.  In the code, I give each set of data a different name.


files = FileNames["*txt"]

strm6 = OpenRead["Au6002.txt"]
Skip[strm6, Record, 4, NullRecords -> False]       (*First 4 lines of each
files contains non-numeric values, so skip these lines*)
six= ReadList[strm6, Table[Number, {i, 1, 19}]]     (*Put the data into a
table called by a name*)
Close[strm6]


I would like to take automat this so that I am not copying and pasting file
names so I thought I could use the Block[] funtion and then map the process
onto all the file names in the directory.  When I imput the following code:

Block[{str}, str = OpenRead[#]; Skip[str, Record, 4,
   NullRecords -> False]; ReadList[
    str, Table[Number, {i, 1, 19}]]; Close[str]] & /@ files


my output is:
{Au6001.txt, Au6002.txt, Au6003.txt, Au6004.txt, Au6005.txt}

I do not understand why I get the output I see above.  When I modify the
code above to:


Block[{str}, str = OpenRead[#];
Skip[str, Record, 4,
      NullRecords -> False]; one = ReadList[
      str, Table[Number, {i, 1, 19}]]; Close[str]] & /@ files

and ask for

one // TableForm

then I get the data for the last file in the list of file names which
indicates to me that I may be close in getting this whole thing to work.



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