On 1/13/2015 07:27, Mark Leeds wrote:
Hi All: I was trying to do something with regular expressions in Rcpp
so I piggy backed
heavily off of Dirk's boost.regex example in the Rcpp Gallery where he
takes streams of digits and checks them for machine and human
readability.
Hi!
My problem is actually pretty different and simpler. Essentially, if a
character string ends in "rhofixed" or "norhofixed", then that part of
the character string should be removed. The R code below illiustrates
what I'm trying to do.
But, when I write the Rcpp code to do the same thing and set
Sys.setenv("PKG_LIBS"="-lboost_regex"), I don't get the same result. I
don't know if it's due to the regex engine being different in boost
or I could be doing something else wrong. Thanks for any help.
It does indeed seems simpler than an usual use case for regex. Hence,
perhaps you can go about it differently:
- use `boost::algorithm::ends_with` (from
<boost/algorithm/string/predicate.hpp>) to check whether your predicate
(i.e., a character string ends in "rhofixed" or "norhofixed") holds
- if so, use the `erase` member function
(http://en.cppreference.com/w/cpp/string/basic_string/substr) to get rid
of the substring (note: if one of the aforementioned predicates is
satisfied, then you can trivially infer how long is the substring
subject to removal -- and can thus use, say, the iterator-pair version,
stepping backward from `std::end(your_string)` as needed).
HTH!
Best,
Matt
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