使用查找表在R中重新编码变量

我有一个关于重新编码数据的问题。我想使用查找表，我想知道如何重新编码NA并使用类似于%的方法

样本数据：

gender <- c("Female", "Not Disclosed", "Unknown" , "Male", "Male", "Female", NA)
df_gender <- as.data.frame(gender)
df_gender$gender <- as.character(gender)

性别
df_gender$gender[df_gender$gender == "Female"] <- "F"
df_gender$gender[df_gender$gender == "Male"] <- "M"
df_gender$gender[df_gender$gender %in% c("Unknown", "Not Disclosed", NA)] <- "Missing"

df_gender2 <- as.data.frame(gender)
df_gender2$gender <- as.character(gender)

gender_lookup <- c(Female = "F", Male = "M", Unknown = "Missing", "Not Disclosed" = "Missing")
df_gender2$gender <- gender_lookup[df_gender2$gender]