[英]Conditional dataframe mutations
I have a large data frame that has a lot of string values that I want to clean. 我有一个很大的数据框,其中包含很多要清除的字符串值。
Example: 例:
students <- data.frame(name = c("John", "Jerry", "Bill", "Tom", "Mary", "Bill"),
class = c("A", "B", "-", "#NA", "A", "low"), stringsAsFactors = FALSE)
I want every student who is not in class A,B or C to be set to D. My current solution is: 我希望将不在A,B或C类中的每个学生设置为D。我当前的解决方案是:
'%!in%' <- function(x,y)!('%in%'(x,y))
for(i in 1:nrow(students)) {
if(students$class[i] %!in% c("A", "B", "C")) {
students$class[i] <- "D"
}
}
Is there a better solution than this, preferably with piping as there are a number of columns like this? 有没有比这更好的解决方案,最好是使用管道,因为有许多这样的塔?
Thanks! 谢谢!
We can do this without a loop as assignment is vectorized 我们可以在没有循环的情况下做到这一点,因为赋值是矢量化的
students$class[students$class %!in% c("A", "B", "C")] <- "D"
students
# name class
#1 John A
#2 Jerry B
#3 Bill D
#4 Tom D
#5 Mary A
#6 Bill D
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