Question

我正在研究一个与此类似的数据框：

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)

我在订购数据框时遇到问题 - 基本上我想按以下时间顺序订购数据：

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

给出这个

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

问题是对同一主题进行了测量（DF $ ID = 2）（但访问次数不同，请参阅DF $ VISITNUM）。

我怀疑plyr包中的order（）函数或arrange（）函数是我的朋友，但我的尝试并不富有成效。

任何帮助都将不胜感激。

Sincerily ÿ

Answer 1

是的，您可以使用order()执行此操作，只需指定您希望数据框排序的变量：

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

你也可以使用plyr的arrange()：

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

按R中的特定顺序对数据帧中的列进行排序

1 个答案: