拆分后的数据框列名称 [英] Data frame column names after split
问题描述
执行以下代码时
data <- data.frame( A = c("foo", "foo", "bar", "bar"),
B = c("foo","bar", "foo", "bar"),
C = c("bla", "foo", "bla", "bar"),
D = c(1, 2, 3, 4 ),
E = c(5, 6, 7, 8 ))
ds <- split(data, list(data$A, data$B, data$C), drop=TRUE)
write.table(ds[1], file="foo.csv", append=FALSE, row.names=FALSE)
foo.csv看起来像这样:
foo.csv looks like this:
"bar.bar.bar.A","bar.bar.bar.B","bar.bar.bar.C","bar.bar.bar.D","bar.bar.bar.E"
"bar","bar","bar",4,8
即列名称包含用于拆分的列的内容。如何以通用方式将名称改回原始名称? (我不想分配诸如 A, B等的列名。)
i.e., the column names contain the contents of the columns used to split. How do I change does names back to the original ones in a generic way? (I don't want to assign column names like "A", "B",....)
推荐答案
The split
的输出是列表
。 ds [1]
返回列表
,而 ds [[1]]
返回该第一个列表项中的值。
The output of split
is a list
. ds[1]
returns a list
, while ds[[1]]
returns the value within that first list item.
示例:
ds[1]
# $bar.bar.bar
# A B C D E
# 4 bar bar bar 4 8
ds[[1]]
# A B C D E
# 4 bar bar bar 4 8
获取输出正确地编写为CSV文件,则需要提取实际的 data.frame
,因此需要使用 ds [[1]]
方法。
To get the output properly written as a CSV file, you need to extract the actual data.frame
, so you need to use the ds[[1]]
approach.
write.table(ds[[1]], file="foo.csv", append=FALSE, row.names=FALSE)
如果要编写所有 data.frame
来分隔CSV文件,您可以执行以下操作:
If you wanted to write all of the data.frame
s to separate CSV files, you can do something like:
lapply(names(ds), function(x) {
write.table(ds[[x]], file = paste(x, ".csv", collapse = ""),
append = FALSE, row.names = FALSE)
})
这将创建四个CS工作目录中的V文件(名为bar.bar.bar.csv,bar.foo.bla.csv,foo.foo.bla.csv和foo.bar.foo.csv)。
This will create four CSV files (named bar.bar.bar.csv, bar.foo.bla.csv, foo.foo.bla.csv, and foo.bar.foo.csv) in your working directory.
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