按R中的特定顺序对数据帧中的列进行排序

我正在处理一个与此类似的数据帧：

ID = c("1","1","1","1","1","1","1","2","2","2","2","2","2","2","2","2","2","2","2","2","2") 
TIME = c("0", "0.5", "1","1.5","2","2.5","3","0","0", "0.5","0.5", "1","1","1.5","1.5","2","2","2.5","2.5","3","3") 
OBS = c("0", "0.73", "0.98", "1.24", "2.06","2.56","4.01", "0", "0.03", "0.76", "0.85", "2.13","2.78","3.9", "4.1", "5.4", "5.6", "7.8", "8.0","8.4","8.8") 
VISITNUM = c("1","1","1","1","1","1","1","1","2", "1","2","1","2","1","2","1","2","1","2","1","2") 
DF = data.frame(ID, TIME, OBS, VISITNUM)

我在排序数据帧时遇到问题-基本上我希望按以下时间顺序排序数据：

TIMEORDERED <- c("0","0.5","1","1.5","2","2","2.5","3")

问题是在同一个受试者身上存在测量（DF$ID=2）（但不同的就诊，请参见DF$VISITNUM）

我怀疑plyr包中的order（）函数或arrange（）函数是我的朋友，但我的尝试并没有成功

任何帮助都将不胜感激

真诚地

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Y

是的，您可以使用

order（）

执行此操作，您只需指定数据帧所需的变量：

DF.ordered <- DF[order(DF$ID, DF$VISITNUM, DF$TIME),]

DF.ordered <- DF[order(DF$ID, DF$VISITNUM, DF$TIME),]

library(plyr)
DF.arranged <- arrange(DF, ID, VISITNUM, TIME)