dpb
Posts:
6,849
Registered:
6/7/07
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Re: Extract numbers from table containing text and numbers
Posted:
Feb 5, 2013 9:17 AM
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On 2/5/2013 12:55 AM, Bruno Luong wrote:
> dpb <none@non.net> wrote in message <keplqs$he2$1@speranza.aioe.org>...
>
>>
>> The killer w/ C's i/o functions is their complete inability to
>> "understand" fix-width fields--it's simply absurd that one can't read
>> the equivalent of a Fortran FORMAT(5I1) w/ a record of '101 1' and
>> reliably get 1,0,1,0,1 returned in appropriate variables. In Matlab
>> (and C) that's nearly impossible w/o special handling.
>>
>
> What's problem? The fixed format reading is just take the right column
> of the char matrix. OK you have to count the column, but that's really a
> big deal?
The problem is there's no way to write a format string that will parse
the above example input string correctly w/o actually doing the
character manipulation directly.
Yes, that's a big deal for large files in terms of overhead plus the
necessity of having to write special code to handle it when it should be
a trivial formatting operation.
It's a remnant of the design of C that didn't really consider i/o to be
terribly important it appears...
> Writing with fixed-format with MATLAB is another matter (there is simply
> no easy way of doing it).
I keep hearing this, but on output the fixed-width fields do work at
least reasonably well--there have been several threads on the subject I
can recall over the last several months or so but I can't remember a one
that wasn't solvable pretty easily w/ just the proper formatting strings.
Output works reasonably well; fixed-width non-delimited input is just
broken (by C Library definition which underlies the Matlab formatted i/o
implementation).
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