R-等同于pos函数

Question

I have a string in R which is something like:

File_ABC777_PatientId789.DATA

or can be something like: File_ABC7878787_234_PatientId892.DATA

I want to extract the part of the string that is in between "PatientId" and ".DATA" ...How do I do this in R ? In C# or other languages this is really easy and it's usually done using a String POS Function ... But I can't seem to find a similar function in R ...any thoughts ?

Cheers !!! MadSeb

Answer 1

You could use ?sub :

x <- "File_ABC777_PatientId789.DATA"
sub(x=x, pattern="^.*PatientId([0-9]+).DATA$", replacement="\\1")

Answer 2

I'm not sure what function in other languages you are specifically referring to. As sgibb mentioned, R has plenty of regex type functions.

But if your strings are always in the same format or pattern, you can simply use substr , which simply takes a string, and the start and end positions you want to extract (or replace).