R:如何按行名称从 r 数据框中获取许多(~2000)行 [英] R: How to get many (~2000) rows from an r data frame by row name

问题描述

我有一个带有列标题和行名称的大型数据框，即

I have a large data frame with column headers and row names, i.e.

CountTable = read.table( Data, header=TRUE, row.names=1 )

CountTable = read.table( Data, header=TRUE, row.names=1 )

头部(计数表)

        S1    S2    S3
Row1     9     8     2 
Row2   268   193   282
Row3   635   631   568
Row4     0     2     0
Row5    15     8    10
Row6   416   321   350
... etc

我想从中检索基于名称的行.如果我只有几个要检索，我会使用方括号函数，例如

From which I would like to retrieve rows based on name. If I had only a few to retrieve I would use the square bracket function, e.g.

CountTable[c(Row1", Row3", Row6",]

CountTable[c("Row1", "Row3", "Row6",]

        S1    S2    S3
Row1     9     8     2 
Row3   635   631   568
Row6   416   321   350

但由于我的数据框有 > 20,000 行，我想从中检索 ~2000 行，这不是很实用.我最好的想法是是否有办法从另一个文件(例如，names.txt/.cvs)导入 ~2000 个名称并创建索引向量，例如

But as my data frame has >20,000 rows from which I would like to retrieve ~2000 by their name, this isn't very practical. My best thought was if there is a way of importing the ~2000 names from another file (for example, names.txt/.cvs) and creating an index vector, e.g.

[1] Row1 Row3 Row6 ... Row2000

[1] Row1 Row3 Row6 ... Row2000

这可用于指定在创建数据子集时要检索哪些行?

That could be used to specify which rows to retrieve when creating a subset of my data?

任何解决方案将不胜感激！

Any solution would be greatly appreciated!

推荐答案

如果您基于行名进行子集化，您应该按照

If you're subsetting based on rownames, you should be doing something along the lines of

CountTable[rownames(CountTable) %in% c("row1", "row2", "row3"), ]

要构造行名向量，可以使用

To construct a vector of rownames, you can use

paste0("row", 1:10)
[1] "row1"  "row2"  "row3"  "row4"  "row5"  "row6"  "row7"  "row8"  "row9" 
[10] "row10"

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