清除R dataframe中跨列的重复项

我有一个dataframe，它包含跨三列的副本：

Name      Year     Job1      Job2       Job3
Bob       2011     director  director   chair
Bob       2012     director  chair
Wendy     2011     advisor   chair      advisor
Henry     2010     CEO       president  president

我想删除每行“job1”、“job2”和“job3”列中的重复项：

Name      Year     Job1      Job2       Job3
Bob       2011     director  NA         chair
Bob       2012     director  chair
Wendy     2011     advisor   chair      NA
Henry     2010     CEO       president  NA

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基本上，如果存在重复项，前一列中的值将保持不变，后一列中的值将被删除（例如，如果在“job1”和“job2”之间存在重复项，“job1”中的值将保持不变）。

我们可以按行循环“Job”列，并将重复项替换为

NA

nm1 <- grep('^Job\\d+$', names(df1))
df1[nm1] <- t(apply(df1[nm1], 1, function(x) replace(x, duplicated(x), NA)))

nm1
df1
#   Name Year     Job1      Job2  Job3
#1   Bob 2011 director      <NA> chair
#2   Bob 2012 director     chair      
#3 Wendy 2011  advisor     chair  <NA>
#4 Henry 2010      CEO president  <NA>

df1 <- structure(list(Name = c("Bob", "Bob", "Wendy", "Henry"), Year = c(2011L, 
2012L, 2011L, 2010L), Job1 = c("director", "director", "advisor", 
"CEO"), Job2 = c("director", "chair", "chair", "president"), 
    Job3 = c("chair", "", "advisor", "president")), 
    class = "data.frame", row.names = c(NA, 
-4L))