In the responses below we use this test data:
# test data
v1 <- c("Pic 26 + 25", "Pic 27 + 28", "Pic 28 + 27", "Pic 29 + 30",
"Pic 30 + 29", "Pic 31 + 32")
1) gsubfn
library(gsubfn)
strapply(v1, "(\\d+).*", as.numeric, simplify = c)
## [1] 26 27 28 29 30 31
2) sub This requires no packages but does involve a slightly longer regular expression:
as.numeric( sub("\\D*(\\d+).*", "\\1", v1) )
## [1] 26 27 28 29 30 31
3) read.table This involves no regular expressions or packages:
read.table(text = v1, fill = TRUE)[[2]]
## [1] 26 27 28 29 30 31
In this particular example the fill=TRUE
could be omitted but it might be needed if the components of v1
had a differing number of fields.