toomey8 toomey8 - 11 months ago 50
R Question

Regular Expression in Base R Regex to identify email address

I am trying to use the stringr library to extract emails from a big, messy file.

str_match doesn't allow perl=TRUE, and I can't figure out the escape characters to get it to work.

Can someone recommend a relatively robust regex that would work in the context below?

c("", "", "")->emails
str_match(emails, regex)

42- 42-
Answer Source
> "^[[:alnum:].-_]+@[[:alnum:].-]+$"->regex
> str_match(emails, regex)
[1,] ""      
[2,] ""
[3,] ""

The @-sign is not in need of escaping in regex. And "." and "-" are not special in character classes. If you want to add a requirement for ".com",".co", ".edu", ".org" then you should specify how complete that list needs to be.

As pointed out by M42, this is not a surefire method. In fact it is claimed that there is no sure-fire method: Using a regular expression to validate an email address