within one of the variables of a data set within R I have certain values that I want to change to NA for hot deck imputation. The possible values within it are: "Missing", "Inapplicable", "Refusal", "Don't Know", "Not mentioned" and "Mentioned". Not quite sure how to change all except Mentioned and Not Mentioned to NA values.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
