Regex matching that gives byte offset?
On Monday 02 November 2009 13:41:45 Prof Brian Ripley wrote:
On Mon, 2 Nov 2009, Johannes Graumann wrote:
Hmmm ... that should do it, thanks. But how would one use this on a file without reading it into memory completely?
?file, ?readLines, ?readBin will tell you about connections.
... all of which I only get to read by the line and a regexpr on that will not give me the absolute offset. "grep -buo" on the unix command line is really fast for this. If I can't find the native R equivalent, I'm of a mind to do this via a sys call - ugly and not portable, but SOOO fast ... is it possible in R? Joh
Joh On Wednesday 28 October 2009 16:29:00 Prof Brian Ripley wrote:
Do you mean like regexpr() (on the same help page)? Depending on your locale, you might actually prefer the character offset: if you want to match in a MBCS and have byte offsets you will need to work a bit harder if useBytes=TRUE is not sufficient for you. On Wed, 28 Oct 2009, Johannes Graumann wrote:
Hi, Is there any way of doing 'grep' ore something like it on the content of a text file and extract the byte positioning of the match in the file? I'm facing the need to access rather largish (>600MB) XML files and would like to be able to index them ... Thanks for any help or flogging, Joh
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