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Remove all rows where length of string is more than n（4个答案）
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我们在“标识符”列中有值，其值范围为7-11个字符/数字。是否有方法删除值超过9个字符的行？

Identifier    X1  X2  X3  X4
2021047.PR    0   0   1   9
2021047.YB    3   0   3   0
2021047.C     0   5   0   3
2020048       8   6   2   0
2021049.Arv   7   0   3   0
2021049.BR    0   3   0   8
2021049.C     3   0   0   1
2021050       4   0   7   0

预期结果：首选Dplyr/Tidy结果

Identifier    X1  X2  X3  X4
2021047.C     0   5   0   3
2020048       8   6   2   0
2021049.C     3   0   0   1
2021050       4   0   7   0

structure(list(Identifier = c("2021047.PR", "2021047.YB", "2021047.C", 
"2020048", "2021049.Arv", "2021049.BR", "2021049.C", "2021050"
), X1 = c(0L, 3L, 0L, 8L, 7L, 0L, 3L, 4L), X2 = c(0L, 0L, 5L, 
6L, 0L, 3L, 0L, 0L), X3 = c(1L, 3L, 0L, 2L, 3L, 0L, 0L, 7L), 
    X4 = c(9L, 0L, 3L, 0L, 0L, 8L, 1L, 0L)), class = "data.frame", row.names = c(NA, 
-8L))