I modified my question in "search and convert string function "

peng shen <michael_shen <at> hotmail.com> writes:

: 
: Hi ,all R-helper!
: I modified my  question  in "search and convert string function".
: I want to do this kind of operation In R enviroment :
: For example :
: R <- 4
: testString <- "I love %R%"
: then search this testString, when find beginning and end symbol"%",get a new 
: substring "%R%".
: then get rid of symbole"%",replace string"R" by R(numeric )
: So the final string is "I love 4"
: 
: How can I implement? if there is not this kind of function ,how can I write 
: function in C and implement in R.
: Thanks advance
: 

The function in my response to your original post can already do that:

R> interp("I love %R%", pre = "%", post = "%")
[1] "I love 4"