How do I replace brackets using regular expressions in R?

Question

I'm sure this is a really easy question. I'm quite familiar with RegEx in R in the meantime, but I just can't get my head around this one.

Suppose, we have this string:

a <- c("a b . ) ] \"")

Now, all I want to do is to delete the quotes, the dot, the closing paranthesis and the closing brackets.

So, I want: "a b".

I tried:

gsub("[.\\)\"\\]]", "", a)

It doesn't work. It returns: "a b . ) ]" So nothing gets removed.

As soon as I exclude the \\] from the search pattern, it works...

gsub("[.\\)\"]", "", a)

But, of course, it doesn't remove the closing brackets!

What have I done wrong?!?

Thanks for your help!

Answer 1

a <- c('a b . ) ] "');
gsub('\\s*[].)"]\\s*','',a);
## [1] "a b"

When you want to include the close bracket character in a bracket expression you should always include it first within the brackets; that causes it to be taken as a character within the bracket expression, rather than as the closing delimiter of the bracket expression.