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Re: Problems reading text files with embedded delimiters

  • To: mathgroup at smc.vnet.net
  • Subject: [mg125611] Re: Problems reading text files with embedded delimiters
  • From: Rodrigo Murta <murta at rodrigomurta.com>
  • Date: Wed, 21 Mar 2012 05:47:55 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <jk9bfb$bo1$1@smc.vnet.net>

On Mar 20, 4:26 am, Mark Coleman <markspcole... at gmail.com> wrote:
> Hi,
>
> I'm struggling with importing a large flat file into Mathematica. The file,
> which was pulled off one of my company's legacy mainframe systems,
> contains about 100 fields and several million rows, including a mix of
> dates, reals, and text. The fields are delimited by commas.
>
> One of the text fields, however, is quite large and contains commas,
> line feeds, carriage returns, etc -- lots of characters commonly used
> as delimiters. It is also a variable length field. There does not seem
> to be anything characters within the field that would allow the
> specification of a simple delimiter. I've tried the default Import[]
> command as well as various permutations of ReadList[] using Record,
> Word, and String specifications.
>
> I'm wondering if anyone could suggest an approach that would allow me
> to read this file. More precisely, is there a way to avoid reading
> characters embedded in the large text field that Mathematica thinks are field
> delimiters?
>
> Thanks,
>
> Mark

Hi Mark
I didn't completely get your point. What is your delimiter? Your large
text is quoted? Can you sendo one example line? Or a toy code?
For large text string you could use some low level programming.
Maybe this tutorial could help you:
http://reference.wolfram.com/mathematica/guide/LowLevelFileOperations.html
Go to the stream topic.
best regards
Murta



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