在 R 中读取两行标题 [英] Reading two-line headers in R

问题描述

当标题有两个必要的标题行时，将文件读入 R 的最佳方法是什么?

What is the best way to read a file into R when the header has two necessary lines for the header?

这种情况一直发生在我身上，因为人们经常使用一行作为列名，然后在其下方包含另一行作为度量单位.我不想跳过任何东西.我想要名字和单位.

This happens to me all the time, as people often use one line for the column name and then include another line underneath it for the unit of measurement. I don't want to skip anything. I want the names and the units to carry through.

具有两个标题的典型文件可能如下所示:

trt   biomass    yield
crop    Mg/ha    bu/ac
C2      17.76   205.92
C2      17.96   207.86
CC      17.72   197.22
CC      18.42   205.20
CCW     18.15   200.51
CCW     17.45   190.59
P       3.09    0.00
P       3.34    0.00
S2      5.13    49.68
S2      5.36    49.72

推荐答案

我会做两个步骤，假设我们知道第一行包含标签，并且总是有两个标题.

I would do two steps, assuming we know that the first row contains the labels, and there are always two headers.

header <- scan("file.txt", nlines = 1, what = character())
data <- read.table("file.txt", skip = 2, header = FALSE)

然后添加字符向量 header 作为 names 组件:

Then add the character vector header on as the names component:

names(data) <- header

对于您的数据，这将是

header <- scan("data.txt", nlines = 1, what = character())
data <- read.table("data.txt", skip = 2, header = FALSE)
names(data) <- header

head(data)

>     head(data)
  trt biomass  yield
1  C2   17.76 205.92
2  C2   17.96 207.86
3  CC   17.72 197.22
4  CC   18.42 205.20
5 CCW   18.15 200.51
6 CCW   17.45 190.59

如果你想要单位，按照@DWin 的回答，然后在第 2 行做第二个 scan()

If you want the units, as per @DWin's answer, then do a second scan() on line 2

header2 <- scan("data.txt", skip = 1, nlines = 1, what = character())
names(data) <- paste0(header, header2)

> head(data)
  trtcrop biomassMg/ha yieldbu/ac
1      C2        17.76     205.92
2      C2        17.96     207.86
3      CC        17.72     197.22
4      CC        18.42     205.20
5     CCW        18.15     200.51
6     CCW        17.45     190.59

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