根据R中的名称循环复制粘贴值

I have a dataset "datP" that I am trying to add a new variable named "threshold" to. The values I need to add are stored in a test dataframe that looks like this (country codes as rownames and income as the sole variable). I calculated those income values for each country in my main dataset ("DatP") and saved the resulting vector as a "test" dataframe with 32 observations for one variable. I have a dataset "datP" that I am trying to add