重新排序数据列

Question

我试图重新排列我的专栏，但无法弄清楚如何对我的专栏中的某个订单进行排序。 例如。 我有以下data.frame

df <- data.frame(name=c("a","a","a","b","b","c","c","c","c"), time=c("screen","third","second","first","second","fourth","third","first","screen"), first_values=c("0.11", "0.23", "0.03", "0.4", "0.10", "0.25", "0.87","0.11","0.21"), second_values=c("0.05", "0.32", "0.63", "0.67", "0.10", "0.25", "0.87","0.11","0.91"))

target.time <- c("zeros", "screen", "first", "second", "third", "fourth")

所以我的目标是按名称和时间排序； 但是时间必须按照target.time描述的顺序。

通过执行以下操作，我可以实现多列排序；

df_reorder <- df[order(df$name, df$time), ]

但是我不知道如何用target.time order来排序时间，而df $ name对于相关行仍然是唯一的。

Answer 1

一种常见的方法是重新排序df$time的因子水平，然后使用order 。

# reassign factor levels according to target.time
df$time <- factor(df$time, levels=target.time)

# order data.frame
df[order(df$name, df$time),]
  name   time first_values second_values
1    a screen         0.11          0.05
3    a second         0.03          0.63
2    a  third         0.23          0.32
4    b  first          0.4          0.67
5    b second         0.10          0.10
9    c screen         0.21          0.91
8    c  first         0.11          0.11
7    c  third         0.87          0.87
6    c fourth         0.25          0.25