使用列作为类别重塑

Question

重塑此数据框的任何 R 代码来自：

	big	small	year
1	70.9	60.3	2000
2	70.7	40.4	2001
3	70.8	55.2	2002

至：

	size	values	year
1	big	70.9	2000
2	small	60.3	2000
3	big	70.7	2001
4	small	40.4	2001
5	big	70.8	2002
6	small	55.2	2002

在 base R 中有没有一种巧妙的方法（如果不是包解决方案也可以）？

感谢任何帮助！

Answer 1

您正在寻找dplyr包

中的pivot_longer()函数

library(dplyr)

df %>% pivot_longer(cols=c('big', 'small'), names_to='size', values_to='values'))

Answer 2

基本 R 选项

> cbind(year = df$year, rev(stack(df[1:2])))[order(c(row(df[1:2]))),]
  year   ind values
1 2000   big   70.9
4 2000 small   60.3
2 2001   big   70.7
5 2001 small   40.4
3 2002   big   70.8
6 2002 small   55.2

一个data.table选项

> setorder(melt(setDT(df), id.vars = "year"), "year")[]
   year variable value
1: 2000      big  70.9
2: 2000    small  60.3
3: 2001      big  70.7
4: 2001    small  40.4
5: 2002      big  70.8
6: 2002    small  55.2

Answer 3

正如 OP 提到的 base R 解决方案，这里有一个 reshape

out <- reshape(df1, idvar = "year", direction = 'long',
    times = names(df1)[1:2], varying = list(1:2), timevar = "size", 
       v.names = "values")
row.names(out) <- NULL

-输出

> out
  year  size values
1 2000   big   70.9
2 2001   big   70.7
3 2002   big   70.8
4 2000 small   60.3
5 2001 small   40.4
6 2002 small   55.2

数据

df1 <- structure(list(big = c(70.9, 70.7, 70.8), small = c(60.3, 40.4, 
55.2), year = 2000:2002), class = "data.frame", row.names = c("1", 
"2", "3"))

使用列作为类别重塑

Reshape using columns as categories

r

reshape

dataframe

数据