如何在R中将多列更改为仅一列的数据帧

问题描述

我有一个像这样的数据框

x <- data.frame("Name" = c("John","Dora"),"SN" = 1:2,"SN_1" = 7:8,"SN_2" = 5:6 )

  Name SN SN_1 SN_2
1 John  1    7    5
2 Dora  2    8    6

我想将其转换为：

  Name SN
1 John  1
2 Dora  2
3 John  7
4 Dora  8
5 John  5
6 Dora  6

解决方法

library(data.table)
setDT(x)
melt(x,id.vars = "Name",measure.vars = patterns(c("SN")))[,.(Name,SN = value)]