How can I get all substrings matching a regex from another string in R

Question

I have a string: "C:/This/is/a/windows/path/file20110312name20120221.csv".

I want to extract all dates (e.g. [0-9]{8}).

Generally, how can I extract sub-strings matching a pattern from a bigger string?

Well, have you read `?regex` and the help files linked under "see also"? — Roland, Jul 04 '13 at 08:35
Looks like you learned a valuable lesson on finding functions ... — Roland, Jul 04 '13 at 09:36
yep... actually I am not a newbie in R so It also means that the search for functionality process might need improvement, but I guess this is a hard problem for the R guys. — statquant, Jul 04 '13 at 10:12

score 6 · Accepted Answer · edited May 23 '17 at 12:11

6

It is advised to supplement your question with a reproducible example (How to make a great R reproducible example?)

Is this what you look for ?

s <- "C:/This/is/a/windows/path/file20110312name20120221.csv"
regmatches(s, gregexpr("[0-9]{8}", s))

edited May 23 '17 at 12:11

Community

answered Jul 04 '13 at 08:42

Karl Forner

Yes exactly that ... where does this regmatches come from... ? – statquant Jul 04 '13 at 08:43
`regmatches()` was added in R 2.14.0. – Jimbo Jul 04 '13 at 08:46
1

can't find it on ?regex or ?grep though, this is going to cost me some points but thanks at least I learnt something – statquant Jul 04 '13 at 08:47
look in the @seealso section of ?grep... I agree it is not that easy to find, I was glad when I did ! – Karl Forner Jul 04 '13 at 08:49
damn ! Indeed ! thanks mate this stuff is so usefull ! – statquant Jul 04 '13 at 08:54

1 Answers1