Lua gsub - How to set max character limit in regex pattern

Question

From strings that are similar to this string:

|cff00ccffkey:|r value

I need to remove |cff00ccff and |r to get:

key: value

Answer 1

Lua patterns do not support range/interval/limiting quantifiers.

You may repeat %w alphanumeric pattern eight times:

local newString = string.gsub("|cff00ccffkey:|r value", "|c%w%w%w%w%w%w%w%w", "")
newString = string.gsub(newString, "|r", "")
print(newString)
-- => key: value

See the Lua demo online.

You may also make it a bit more dynamic if you build the pattern like ('%w'):.rep(8):

local newString = string.gsub("|cff00ccffkey:|r value", "|c" ..('%w'):rep(8), "")

See another Lua demo.

If your strings always follow this pattern - |c<8alpnum_chars><text>|r<value> - you may also use a pattern like

local newString = string.gsub("|cff00ccffkey:|r value", "^|c" ..('%w'):rep(8) .. "(.-)|r(.*)", "%1%2")

See this Lua demo

Here, the pattern matches:

• ^ - start of string
• |c - a literal |c
• " ..('%w'):rep(8) .. " - 8 alphanumeric chars
• (.-) - Group 1: any 0+ chars, as few as possible
• |r - a |r substring
• (.*) - Group 2: the rest of the string.

The %1 and %2 refer to the values captured into corresponding groups.