R 使用'；IF'；运算符判断数据框单元格中的给定值是否属于一组值

发布于01月10日

我有一个数据框，上面有动物的名字

x=data.frame(c("lion","tiger","cow","vulture","hyena","leopard","deer","gazzelle"))
colnames(x)=c('animal')

#create sets of animals based on the their diet

carnivore=c("lion","tiger","leopard")
herbivore=c("cow","deer","gazzelle")
omnivore=c("vulture","hyena")

x$diet=NA   ## Add a new column where I want to enter if the animal is one of herbivore, carnivore or omnivore based on the value in x$animal

for (i in 1:(nrow(x))) {
  if (x$animal[i] 'is a subset of' "Omnivore") {
    x$diet[i] = "Omnivore"
  } else if (x$animal[i] 'is a subset of' "Carnivore") {
    x$diet[i] = "Carnivore"
  } else if (x$animal[i] 'is a subset of' "Herbivore") {
    x$diet[i] = "Herbivore"
  }
}

我不太能在R中编写等同于‘is a subset’的代码，我相信它肯定有一个简单的解决方案.如有任何帮助，不胜感激

推荐答案

您的现有代码需要%in% operator:

for (i in 1:(nrow(x))) {
  if (x$animal[i] %in% omnivore) {
    x$diet[i] = "Omnivore"
  } else if (x$animal[i] %in% carnivore) {
    x$diet[i] = "Carnivore"
  } else if (x$animal[i] %in% herbivore) {
    x$diet[i] = "Herbivore"
  }
}

我更喜欢嵌套的ifelse()，而不是forloop + if{}else{}:

x$diet <- ifelse(x$animal %in% carnivore, "Carnivore",
                 ifelse(x$animal %in% herbivore, "Herbivore",
                        ifelse(x$animal %in% omnivore, "Omnivore", "Other")))
x
#     animal      diet
# 1     lion Carnivore
# 2    tiger Carnivore
# 3      cow Herbivore
# 4  vulture  Omnivore
# 5    hyena  Omnivore
# 6  leopard Carnivore
# 7     deer Herbivore
# 8 gazzelle Herbivore