str_count with overlapping substrings

问题

I am trying to count the number of appearances of a substring within a character vector. For example:

lookin<-c("babababa", "bellow", "ra;baba")
searchfor<-"aba"
str_count(lookin, searchfor)

returns: 2 0 1

However, I want it to return '3 0 1' but it isn't picking up on the middle 'aba' in the first item since it is partially used in the first instance (I think).

I found this question but couldn't figure out how to use that with a vector having multiple items.

回答1:

Try:

str_count(lookin, paste0("(?=",searchfor,")"))

[1] 3 0 1

Which, as answered in your link, uses lookahead to match all instances.

来源：https://stackoverflow.com/questions/31609721/str-count-with-overlapping-substrings