在长格式数据框中使用不带列名的熔化将宽格式转换为长格式

如果您需要基本的R解决方案：

data.frame(name_1 = rep(as.character(wide_ex$Column5), each=nrow(wide_ex)),
    name_2 = as.vector(t(wide_ex[, c("Column7", "Column8", "Column9", "Column10")])))

我仍然认为最简洁的方法是与data.table融合：

library(data.table)
setDT(wide_ex)
melt(wide_ex, id.vars = c("Column5"), na.rm=TRUE)[,variable := NULL][]

如果需要关注速度，它将比reshape2显着提高速度。

（附加说明）...附加使用是[]什么？

A) the use of additional [] in data.table is known as chaining. It allows you to perform more operations on preceding []'s.

As you originally indicated, the output of melt produces an unwanted column (variable). variable := NULL removes it. It's essentially the same as doing the following (on your original question):

 long_ex <- melt(wide_ex, id.vars = 5, na.rm=TRUE) 
 long_ex$variable <- NULL

However the use of := does it by reference (and on the same line).

Chaining can be super useful to keep your code nice and concise. Say you wanted to order your output by the first column (as you kind of indicated in your original question). You could do this like so:

melt(wide_ex, id.vars = c("Column5"), na.rm=TRUE)[, variable := NULL][order(Column5)][]

data.table确实是一个了不起的程序包（尤其是在处理中型到大型数据时）。如果您有兴趣，建议您阅读并了解更多信息：https : //github.com/Rdatatable/data.table/wiki