[R] Regular Expression and Pmatch
Peter Dalgaard BSA
p.dalgaard at biostat.ku.dk
Mon Oct 23 20:52:52 CEST 2000
gopher <radar at orinoco.princeton.edu> writes:
> Hi, I wonder if there's a good intro to the pattern matching using R? I'm a perl
> programer and find it too confusing and complex to use regular expressions under R.
> For instance, why does pmatch("d","ad") returns NULL? How would I call the
> functions in order to match any portion of the string? Under what circumstances shall
> backslush be used? I try to extract all strings with ".d", however just couldnt manage
> to do it? Any ideas? Or I have to write my own regex extension ? TIA.
Try help(regexpr). pmatch does *partial* matching - looks for the
string which the first arg is a prefix (well it's really a bit more
complicated...) in the same manner as when actual arguments are
matched to formals.
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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