用R根据行名分隔几个特殊行

Question

我有一个 table，我想按行名称分隔一些行。

            phi      psi
A-MET-0     NA     158.0945
A-VAL-1   -144.914  137.4733
A-LEU-2   -95.021   149.7834
A-SER-3   -82.6826  166.6769
B-GLU-4   -62.5314  -36.2634
H-GLY-5   -59.6463  -42.0355
A-GLU-6   -68.6914  -40.2354
AB-TRP-7  -63.5297  -36.769
A-GLN-8  -64.8056   -38.5128

我会按照下面的命令来分隔特定的行

tor$tbl["A-LEU-2",]

但是当我尝试分隔几行时，出现错误。我使用以下命令分隔几行。

tor$tbl["A-LEU-2":"AB-TRP-7", ]

如何根据行名从 table 中分隔几行？

谢谢指导。

Answer 1

这是执行此操作的函数 -

subset_by_rowname_range <- function(data, start_name, end_name) {
  rn <- rownames(data)
  data[match(start_name, rn) : match(end_name, rn), ]
}
subset_by_rowname_range(df, "A-LEU-2", "AB-TRP-7")

#              phi      psi
#A-LEU-2  -95.0210 149.7834
#A-SER-3  -82.6826 166.6769
#B-GLU-4  -62.5314 -36.2634
#H-GLY-5  -59.6463 -42.0355
#A-GLU-6  -68.6914 -40.2354
#AB-TRP-7 -63.5297 -36.7690

subset_by_rowname_range(df, "H-GLY-5", "A-GLN-8")

#              phi      psi
#H-GLY-5  -59.6463 -42.0355
#A-GLU-6  -68.6914 -40.2354
#AB-TRP-7 -63.5297 -36.7690
#A-GLN-8  -64.8056 -38.5128

数据

df <- structure(list(phi = c(NA, -144.914, -95.021, -82.6826, -62.5314, 
-59.6463, -68.6914, -63.5297, -64.8056), psi = c(158.0945, 137.4733, 
149.7834, 166.6769, -36.2634, -42.0355, -40.2354, -36.769, -38.5128
)), class = "data.frame", row.names = c("A-MET-0", "A-VAL-1", 
"A-LEU-2", "A-SER-3", "B-GLU-4", "H-GLY-5", "A-GLU-6", "AB-TRP-7", 
"A-GLN-8"))

Answer 2

一个简单的解决方案是插入行编号，它可以用作 slice:

的索引

df %>%
  mutate(row = row_number()) %>%
  slice(1:8)

或者，这也可行：这里，which 获取 row.names' 索引，slice 可以通过该索引进行过滤：

df %>%
  slice(which(grepl("A-LEU-2", row.names(df))):which(grepl("AB-TRP-7", row.names(df))))

用R根据行名分隔几个特殊行

Separate several special rows based on row names by R

r

subset