Apostrophes and regular expressions; Cleaning text in R
You can use
gsub("(?i)\\b(?<!')(?![AOI])\\p{L}\\b", "", x, perl=TRUE)
Details:
-
(?i)- case insensitive matching on -
\b- a word boundary -
(?<!')- no'is allowed immediately on the left -
(?![AOI])- the next char cannot beA,I, orO -
\p{L}- any Unicod letter -
\b- a word boundary