使用列名称中的id变量重新整形R [重复](Reshape with id-variable in column names R [duplicate])

 
 
 这个问题在这里已有答案： 
 
 
 
  
 收集多组列[重复] 5个答案 
 
 
 
 
 我已经和R一起工作了很长一段时间，但很少使用reshape或reshape2包。 我目前正在尝试从宽到长格式重塑数据集，其中指标变量是变量名称的一部分。 这是我数据框的当前结构： 
 
mydf <- data.frame(district = c(1:2),
v.mandate = c(1, 3),
s.mandate = c(2, 4),
v.perc = c(.4, .3),
s.perc = c(.5, .6))

> mydf
  district v.mandate s.mandate v.perc s.perc
1        1         1         2    0.4    0.5
2        2         3         4    0.3    0.6
 
 我想将其重新整理为长格式并提取“v”。 和“s。” 作为id变量（在实际数据集中，列表更长）。 见下面的例子。 
 
mydf2 <- data.frame(district = c(1, 1, 2, 2),
party = c("v", "s", "v", "s"),
mandate = c(1, 2, 3, 4),
perc = c(.4, .5, .3, .6))

> mydf2
  district party mandate perc
1        1     v       1  0.4
2        1     s       2  0.5
3        2     v       3  0.3
4        2     s       4  0.6
 
 我尝试过使用reshape和melt函数，但我似乎无法从变量名中提取指标变量。 而是将数据集重新整形为长格式，但将完整的变量名称作为id变量。 见下面的例子。 
 
> melt(mydf, id.vars=1)
  district  variable value
1        1 v.mandate   1.0
2        2 v.mandate   3.0
3        1 s.mandate   2.0
4        2 s.mandate   4.0
5        1    v.perc   0.4
6        2    v.perc   0.3
7        1    s.perc   0.5
8        2    s.perc   0.6
 
 这可能是一个微不足道的问题，但我无法在线找到解决方案。 
 
 非常感谢任何帮助！ 

 
 
This question already has an answer here:
 
 
 
  
 Gather multiple sets of columns [duplicate]  5 answers  
 
 
 
 
I've worked with R for quite some time now, but have made little use of the reshape or reshape2 packages. I'm currently trying to reshape a data set from wide to long format where the indicator variables are part of the variable names. This is the current structure of my data frame:
 
mydf <- data.frame(district = c(1:2),
v.mandate = c(1, 3),
s.mandate = c(2, 4),
v.perc = c(.4, .3),
s.perc = c(.5, .6))

> mydf
  district v.mandate s.mandate v.perc s.perc
1        1         1         2    0.4    0.5
2        2         3         4    0.3    0.6
 
I want to reshape this to long format and extract the "v." and "s." as id variables (in the real data set the list is longer). See example below.
 
mydf2 <- data.frame(district = c(1, 1, 2, 2),
party = c("v", "s", "v", "s"),
mandate = c(1, 2, 3, 4),
perc = c(.4, .5, .3, .6))

> mydf2
  district party mandate perc
1        1     v       1  0.4
2        1     s       2  0.5
3        2     v       3  0.3
4        2     s       4  0.6
 
I have tried using both the reshape and melt functions, but I can't seem to extract the indicator variables from the variable names. Instead, the data set is reshaped into long format, but with the full variable names as id variables. See example below.
 
> melt(mydf, id.vars=1)
  district  variable value
1        1 v.mandate   1.0
2        2 v.mandate   3.0
3        1 s.mandate   2.0
4        2 s.mandate   4.0
5        1    v.perc   0.4
6        2    v.perc   0.3
7        1    s.perc   0.5
8        2    s.perc   0.6
 
It might be a trivial problem, but I haven't been able to find a solution on-line.
 
Greatly appreciate any help!

原文：https://stackoverflow.com/questions/29077443