使用R删除一列中的重复值

Question

我希望删除状态与之前相同的行，只保留具有相同状态的序列中的第一行。

 test[1:100,]
                         time status
    1   2014-07-31 17:00:01.0 0
    2   2014-07-31 17:00:01.2 0
    3   2014-07-31 17:00:01.4 1
    4   2014-07-31 17:00:01.5 1
    5   2014-07-31 17:00:02.2 1
    6   2014-07-31 17:00:02.5 1
    7   2014-07-31 17:00:03.0 1
    8   2014-07-31 17:00:04.0 1
    9   2014-07-31 17:00:04.0 1
    10  2014-07-31 17:00:05.0 1
    11  2014-07-31 17:00:09.0 1
    12  2014-07-31 17:00:10.0 1
    13  2014-07-31 17:00:10.2 1
    14  2014-07-31 17:00:11.2 1
    15  2014-07-31 17:00:11.5 1
    16  2014-07-31 17:00:12.0 1
    17  2014-07-31 17:00:12.5 1
    18  2014-07-31 17:00:12.5 0
    19  2014-07-31 17:00:12.9 1
    20  2014-07-31 17:00:13.4 0

我希望相邻状态的值总是不同的。

                     time status
1   2014-07-31 17:00:01.0 0
3   2014-07-31 17:00:01.4 1
18  2014-07-31 17:00:12.5 0
19  2014-07-31 17:00:12.9 1
20  2014-07-31 17:00:13.4 0

我试过unitest <- subset(test, !duplicated(test[,2]))，该函数删除了所有重复的行，只留下了两行。 我可以使用什么样的功能？

Answer 1

test[c(1, which(diff(test$status) != 0)+1), ]

#                    time status
#1  2014-07-31 17:00:01.0      0
#3  2014-07-31 17:00:01.4      1
#18 2014-07-31 17:00:12.5      0
#19 2014-07-31 17:00:12.9      1
#20 2014-07-31 17:00:13.4      0