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luastring-substitution

Replace a substring in Lua with a pattern

I have a string like this 

     str = '["username"] = "user";
     ["deepscan"] = "true";
     ["token"] = true;
     ["password"] = "krghfkghkfghf";
     ["uploadMethod"] = "JSON";
     ["serviceIsRunning"] = {};
     ["host"] = "sample.com";
     ["instance_ID"] = 405454058;'

I would like the pattern match ["password"] = and have it replace only the string in between the ";' that would be '"krghfkghkfghf" in this instance.

Solution 
  • local function replacePass(configstr, newpass)
    return configstr:gsub("(%[\"password\"%]%s*=%s*)%b\"\"", "%1\"" .. newpass .. "\"")
end

    That won't work if your password contains a double quote inside.