How do I deal with special characters like \^$.?*|+()[{ in my regex?

Question

I want to match a regular expression special character, \\^$.?*|+()[{. I tried:

x <- \"a[b\"
grepl(\"[\", x)
## Error: invalid regular expre         


        

Answer 1

I think the easiest way to match the characters like

\^$.?*|+()[

are using character classes from within R. Consider the following to clean column headers from a data file, which could contain spaces, and punctuation characters:

> library(stringr)
> colnames(order_table) <- str_replace_all(colnames(order_table),"[:punct:]|[:space:]","")

This approach allows us to string character classes to match punctation characters, in addition to whitespace characters, something you would normally have to escape with \\ to detect. You can learn more about the character classes at this cheatsheet below, and you can also type in ?regexp to see more info about this.

https://www.rstudio.com/wp-content/uploads/2016/09/RegExCheatsheet.pdf