我有一个类似于以下内容的分类数据集:
A<-data.frame(animal=c("cat","cat","cat","dog","dog","dog","elephant","elephant","elephant"),
color =c(rep(c("blue","red","green"),3)))
我想订购它,以便动物用狗,然后大象,然后猫,然后颜色分为绿色,蓝色,然后红色。所以最后它看起来像
狗绿色,狗蓝色,狗红色,大象绿色,大象蓝色,...
应明确指定级别:
A$animal <- factor(A$animal, levels = c("dog", "elephant","cat"))
A$color <- factor(A$color, levels = c("green", "blue", "red"))
然后您同时按2列排序:
A[order(A$animal,A$color),]
# animal color
# 6 dog green
# 4 dog blue
# 5 dog red
# 9 elephant green
# 7 elephant blue
# 8 elephant red
# 3 cat green
# 1 cat blue
# 2 cat red
另一件值得注意的事情 - 您不必转换类来执行此操作。您可以简单地按变量因子排序。因此,如果需要,保留现有数据结构内的例如字符类。
例如,使用上面的例子:
A[order(factor(A$animal, levels = c("dog", "elephant","cat")) ,factor(A$color, levels = c("green", "blue", "red"))),]
取决于课堂保护是否重要。对我个人而言,这将是一个更典型的用例。 HTH
你也可以使用match
- 你不改变列类也不做factor
转换。
animalOrder = c("dog", "elephant","cat")
colorOrder = c("green", "blue", "red")
A[ order(match(A$animal, animalOrder), match(A$color, colorOrder)), ]
animal color
6 dog green
4 dog blue
5 dog red
9 elephant green
7 elephant blue
8 elephant red
3 cat green
1 cat blue
2 cat red