list - 要在R中列出的文本文件

Question

我有一个很大的文本文件，每行中都有可变数量的字段。每行中的第一个条目对应于一个生物途径，每个随后的条目对应于该途径中的一个基因。前几行可能看起来像这样

path1   gene1 gene2
path2   gene3 gene4 gene5 gene6
path3   gene7 gene8 gene9

我需要将此文件读入R作为列表，每个元素是一个字符 vector ，列表中每个元素的名称是该行的第一个元素，例如:

> pathways <- list(
+     path1=c("gene1","gene2"), 
+     path2=c("gene3","gene4","gene5","gene6"),
+     path3=c("gene7","gene8","gene9")
+ )
> 
> str(pathways)
List of 3
 $ path1: chr [1:2] "gene1" "gene2"
 $ path2: chr [1:4] "gene3" "gene4" "gene5" "gene6"
 $ path3: chr [1:3] "gene7" "gene8" "gene9"
> 
> str(pathways$path1)
 chr [1:2] "gene1" "gene2"
> 
> print(pathways)
$path1
[1] "gene1" "gene2"

$path2
[1] "gene3" "gene4" "gene5" "gene6"

$path3
[1] "gene7" "gene8" "gene9"

...但是我需要自动执行数千行。我看到了 similar question posted here previously，但是我不知道如何从该线程执行此操作。

提前致谢。

Answer 1

这是一种实现方法:

# Read in the data
x <- scan("data.txt", what="", sep="\n")
# Separate elements by one or more whitepace
y <- strsplit(x, "[[:space:]]+")
# Extract the first vector element and set it as the list element name
names(y) <- sapply(y, `[[`, 1)
#names(y) <- sapply(y, function(x) x[[1]]) # same as above
# Remove the first vector element from each list element
y <- lapply(y, `[`, -1)
#y <- lapply(y, function(x) x[-1]) # same as above