r子字符串

Question

gsub(".*s$", "", c("book", "books", "chair", "tables"), perl=T)

gsub（“。* s $”，“”，c（“ book”，“ books”，“ chair”，“ tables”），perl = T）

Answer 1

As Joran says in his comment, you are matching too much. .*s$ matches any string that ends with an s . The entire string is matched, and thus the entire string is replaced with an empty string.

You want this:

gsub("s$", "", c("book", "books", "chair", "tables"))

Note that you don't need perl=TRUE for this expression.

Answer 2

There could well be words that end in an "s" that are not plurals and you might not want to remove the last "s". Here is another approach, using the tm package, but it stems "tables".

text <- c("book", "books", "chair", "tables", "glass", "mess")
library(tm)
text.stem <- stemDocument(text)
> text.stem
[1] "book"  "book"  "chair" "tabl"  "glass" "mess"