Q:

Split a string by a plus sign (+) character

I have a string in a data frame as: "(1)+(2)"
I want to split with delimiter "+" such that I get one element as (1) and other as (2), hence preserving the parentheses. I used strsplit but it does not preserve the parenthesis.

A:

Use
strsplit("(1)+(2)", "\\+")

or
strsplit("(1)+(2)", "+", fixed = TRUE)

The idea of using strsplit("(1)+(2)", "+") doesn't work since unless specified otherwise, the split argument is a regular expression, and the + character is special in regex. Other characters that also need extra care are 

?
*
.
^
$
\
|
{ }
[ ]
( ) 

