Regex to replace matches but also ignore when matches within quotes - r

Question

Trying to match and replace "and" or "or" to "&" and "|" when it occurs outside of quotes except when they occur within quotes.
Quotes could be single(') or double(").
The string is as follows:
Industry ='Education' or Industry =\"Energy\" or Industry = 'Financial or Bank' or Industry = 'Hospitality' or Industry = \"Food and Beverage\" and Industry = 'Utilities'
Expected output:
Industry ='Education' | Industry =\"Energy\" | Industry = 'Financial or Bank' | Industry = 'Hospitality' | Industry = \"Food and Beverage\" & Industry = 'Utilities'
I know that we might have to use lookarounds but cant figure out how. I am using stringr package in R for all my regex manipulations.
Let me know if you need more info.

Answer 1

You should consider an approach to match double- and single-quoted substrings to omit them and only process and or or in all other contexts. The easiest way is to use gsubfn where you may pass a PCRE regex that will do exactly that:
> library(gsubfn)
> x <- "Industry ='Education' or Industry =\"Energy\" or Industry = 'Financial or Bank' or Industry = 'Hospitality' or Industry = \"Food and Beverage\" and Industry = 'Utilities'"
> pat = "(?:\"[^\"]*\"|'[^']*')(*SKIP)(*F)|\\b(and|or)\\b"
> gsubfn(pat, ~ ifelse(z=="or","|", "&"), x, backref=0, perl=TRUE)
[1] "Industry ='Education' | Industry =\"Energy\" | Industry = 'Financial or Bank' | Industry = 'Hospitality' | Industry = \"Food and Beverage\" & Industry = 'Utilities'"
The (?:\"[^\"]*\"|'[^']*')(*SKIP)(*F)|\\b(and|or)\\b pattern will match:
(?: - an alternation group:
\"[^\"]*\" - a double quoted substring having no double quotes inside
| - or
'[^']*' - a single quoted substring
) - end of the group
(*SKIP)(*F) - discard the match, proceed looking for the next match
| - or
\\b(and|or)\\b - Group 1: either an and or or as a whole word.
See the regex demo.
Depending on how the literal " and ' are escaped inside "..." and '...' you will need to adjust the (?:\"[^\"]*\"|'[^']*') part of the regex.
The ~ ifelse(z=="or","|", "&") part is a callback function that receives the only argument (named z inside this function) and its contents are the match value you get from the regex (i.e. either or or and). If the match value is equal to or, the match is substituted with |, else, with &.

Answer 2

this is an ugly way to do it, but it's working for your specific case:
For Or :
(?:'|")(?:.*?)(?:'|")(?:.*?)(or)(?:.*?)
For And :
(?:'|")(?:.*?)(?:'|")(?:.*?)(and)(?:.*?)
i recommend using https://regex101.com/ to help build and test your regex

Answer 3

Your question has potential problems, because nested content may not be handled well or at all by a single regex. That being said, if we assume that the or values you want to replace by pipes always occur after a quoted string, then we can try the following:
gsub("([\"'])\\s*or", "\\1 |", input)
[1] "Industry ='Education' | Industry =\"Energy\" | Industry = 'Financial or Bank' |
Industry = 'Hospitality' | Industry = \"Food and Beverage\" and Industry = 'Utilities'"
By inspection, the or values occurring inside quoted strings are surrounded on both sides by unquoted words. Obviously, this may break down upon seeing other data, or more nested content.
Demo