[plt-scheme] How to get tokenize a string?

From: Laurent (laurent.orseau at gmail.com)
Date: Sun Nov 8 03:59:34 EST 2009


You might not need a tokenizer.
Probably something like that should do it:

    "my-file.txt" #:mode 'text
  (lambda ()
    (let loop ([numbers '()]
               [line (read-line)])
      (if (eof-object? line)
          (reverse numbers)
            (filter (lambda(x)x)
                    (map string->number
                         (regexp-split #px"\\s+" line)))

Lines are read one by one, and each line is split on spaces with
regexp-split, then empty values are removed (with filter), strings are
turned into numbers with string->number, and all the values are consed into
a list of list of numbers.

Hope this helps,

On Sun, Nov 8, 2009 at 08:41, <krhari at ccs.neu.edu> wrote:

> Hi,
> I have a file which contains data like this
>  2.5500000e-002  3.6238983e-002
>  2.5500000e-002  3.6238638e-002
>  2.5500000e-002  3.6237603e-002
> ...
> I am working on a small animation I need these numbers to calculate some
> things there... I am using 2htdp/universe teachpack...
> I actually found string->tokenize function in SRFI doc... Can I use it? If
> yes can anyone guide me how to use SRFI? If no is there any other way out
> other than converting the file into a string then using sting->list and
> doing it in brute force way?
> If I use file->string, I get a string like this
> "  2.5500000e-002  3.6238983e-002\r\n  2.5500000e-002  3.6238638e-002\r\n
>  2.5500000e-002  3.6237603e-002\r\n"
> Please help me out...
> Thanks
> Hari
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