gsub() in R is not replacing '.' (dot)

Question

I want to replace dots in "2014.06.09" to "2014-06-09". I am using gsub() function for it. If

x <-  "2014.06.09"
gsub('2', '-' ,x)
# [1] "-014.06.09"

But when I try

gsub('.', '-', x)
# [1] "----------"

instead of "2014-06-09".

class(x)
# "character"

Can some suggest me a way to get this right and also why it is not working for '.' (dot)

Solution 1

You may need to escape the . which is a special character that means "any character" (from @Mr Flick's comment)

 gsub('\\.', '-', x)
 #[1] "2014-06-09"

Or

gsub('[.]', '-', x)
#[1] "2014-06-09"

Or as @Moix mentioned in the comments, we can also use fixed=TRUE instead of escaping the characters.

 gsub(".", "-", x, fixed = TRUE)

Solution 2

For more complex tasks the stringr package could be interesting

https://cran.r-project.org/web/packages/stringr/vignettes/stringr.html

https://github.com/rstudio/cheatsheets/raw/master/strings.pdf

library(stringr)

str_replace_all(x,"\\.","-")
## [1] "2014-06-09"

Or

str_replace_all(x,"[.]","-")
## [1] "2014-06-09"

Comments

[akrun]

@drmariod Yes, that is an alternative

[Molx]

Or use fixed = TRUE which doesn't use regex but instead just searches for the characters. gsub(".", "-", x, fixed = T)

[Mehdi Abbassi]

what if we want to change every single punctuation signs with something else like space? In dealing with texts from social media or reviews I come up with a lot of dots or other punctuation signs between words, because the forgot to use space after they finish the sentence.

[akrun]

@MehdiAbbassi You can do gsub("[[:punct:]]", " ", x)