[R] Wish list: add an "until" or "EOF.marker" parameter to scan & rea dLines

[ripley@stats.ox.ac.uk]

Why is this necessary?  There are plenty of ways to do this already via
connections, e.g copy line-by-line to an anonymous file connection and
then scan from that.

Yes, it is useful, and that's why people already supplied you with a more
general tool, namely connections.  Please do look at the internals of scan
before suggesting complicating it further: it is already close to
unmaintainable.

I don't think R-help is the place for wishlist items: there is R-devel and
the R-bugs list has a wishlist section too (but please note that this gets
little action due to the perceived usefulness of the wishes).

On Fri, 27 Dec 2002 Mark.Bravington at csiro.au wrote:

> A bit late for Santa, but on my wish-list nevertheless:
>
> is there any chance that "scan" and "readLines" could be extended to take a
> parameter "until" or "EOF.marker", which would be a character string that
> (if encountered while reading) would cause the reading to stop, just as if
> an end-of-file had been found? [But leaving a connection open, so that
> subsequent calls could read the rest of the file.] Compatibility could be
> ensured by making "until" default to as.character( NA), which can never be
> encountered. If the "until" string isn't encountered when reading, then
> reading continues until a real end-of-file (or the "n" parameter is
> satisfied).
>
> This would be useful in all sorts of contexts; one example is in processing
> a single data file that's made up of multiple segments each of different
> formats.
>
> cheers
> Mark
>
> *******************************
>
> Mark Bravington
> CSIRO (CMIS)
> PO Box 1538
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> Mark.Bravington at csiro.au
>
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
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