Grep在R中使用正则表达式

Question

I have a vector of character strings which I need to grep through.

The term I would like to grep is "A-10", but I would like it only to pick up rows where "A-10" is an independent word (eg "A-10 aircraft maintenance" and NOT "WQDA-10-ASP").

Which regular expression(s) would allow me to grep for "A-10" as an separate word and not part of a different word or string?

Answer 1

How about this:

abc <- c('A-10 maintanance', 'WQDA-10-ASP')
grep('(^|\\s)A-10($|\\s)', abc)

where (^|\\\\s) means beginning of string or whitespace, and ($|\\\\s) means end of line or whitespace

Also take a look at the stringr package if you want some nice regex functions.