Validating email adresses in R

July 5, 2012

(This article was first published on Nicebread » R, and kindly contributed to R-bloggers)

I currently program an automated report generation in R – participants fill out a questionnaire, and they receive a nicely formatted pdf with their personality profile. I use knitr, LaTex, and the sendmailR package.

Some participants did not provide valid email addresses, which caused the sendmail function to crash. Therefore I wanted some validation of email addresses – here’s the function:

^?View Code RSPLUS

isValidEmail <- function(x) {
	grepl("\\<[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,}\\>", as.character(x), ignore.case=TRUE)
}

Let’s test some valid and invalid adresses:

^?View Code RSPLUS

# Valid adresses
isValidEmail("[email protected]")
isValidEmail("[email protected]")
isValidEmail("[email protected]  ")
isValidEmail("    [email protected]")
isValidEmail("[email protected]")
isValidEmail("[email protected]")
 
# invalid addresses
isValidEmail("felix@nicebread")  
isValidEmail("felix@nicebread@de")
isValidEmail("felixnicebread.de")

The regexp is taken from www.regular-expressions.info and adapted to the R style of regexp. Please note the many comments (e.g., here or here) about “Is there a single regexp that matches all valid email adresses?” (the answer is no).

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