Replace "1Don't do that" with "_1Don_t_do_that"

Question

I need to modify the keys of a key value file as follows:

"1Don't do that" = "some value"

to

"_1Don_t_do_that" = "some value"

• prepend with underscore if string starts with a number
• replace any non alphanumeric char with underscore
• do not alter the value string

I can do it in several steps if necessary

I've tried things like \"\w+[^\w]\w+\" = but it doesn't account for multiple spaces and does not single or double quotes.

Any help is welcome.

Answer 1

Assuming that none of your quotes are escaped, this should work:

(?:(?<=")(?=\d)|[^\w"])(?=[^"]*"\s*=)

This matches

• either the position between " and a digit
• or a non-alphanumeric character (except a quote),

but only if they are followed by a single quote and an equals sign.

See it live on regex101.

Answer 2

I’m not sure what regex flavor Xcode uses, but as long as it supports positive lookahead (?=), this series of replacements should work:

1. Prepend with underscore if string starts with a number
   • find: ^"(?=\d)
   • replace all: "_
2. Replace any non alphanumeric char with underscore, making sure that the value string is after, not part of, what we're changing.
   • find: [^a-zA-Z0-9](?=[^"]*"\s*=\s*"[^"]*")
   • replace all: _

The second step assumes that quote characters never occur in the value string; tell me if you need to handle backslash-escaped quote characters.