Matching entire string in R

Question

Consider the following string:

string = \"I have #1 file and #11 folders\"

I would like to replace the pattern #1 with the word

Answer 1

Use the space after #1 to your advantage:

gsub("#1 ", "one ", string, fixed = TRUE)

[1] "I have one file and #11 folders"

Answer 2

If you use the perl=TRUE argument to tools like gsub then the perl regex engine will be used which has some options that could help.

The pattern "#1\\b" will match #1 followed by a word boundary, so it would match #1, but not #11 (since there is no boundary between the 2 1's). There are also tools for positive and negative look ahead which look for things following your pattern (like the word file maybe), but does not include them in the part to be replaced.

Answer 3

I'm not sure if I understood right, but does this help -

a <- "I have #1 file and #11 folders"
b <- "I have #1file and #11 folders"
c <- "I have #1,file and #11 folders"

> gsub(x = a, pattern = "#1.*file", replacement = "one file")
[1] "I have one file and #11 folders"
> gsub(x = b, pattern = "#1.*file", replacement = "one file")
[1] "I have one file and #11 folders"
> gsub(x = c, pattern = "#1.*file", replacement = "one file")
[1] "I have one file and #11 folders"