r - R：将稀有值替换为“其他”(R: Replace rare values by “others”)

Question

I have the following problem: I have a data frame df with many variables.

(我有以下问题：我有一个带有许多变量的数据框df 。)

One variable is df$size (non-numeric).

(一个变量是df $ size （非数字）。)

Now I want to replace all sizes with less than 20 observations by the term "other".

(现在，我要用“其他”一词替换少于20个观察值的所有大小。)

sort(table(df$size))

This gives me an overview of the values I want to replace.

(这为我提供了我要替换的值的概述。)

But how do I replace them in my df?

(但是，如何在df中替换它们？)

df$size[sort(table(df$size))<20]="other"

That does not work.

(那行不通。)

Thank you!

(谢谢！)

  ask by Christopher translate from so

Answer 1

Works with something along this

(与此一起工作)

set.seed(123)
df <- data.frame(size = as.character(sample(1:5, size = 100, replace = TRUE)),
                 stringsAsFactors = FALSE)
tabs <- sort(table(df$size))
tab <- tabs[tabs < 20]

df$size[which(df$size %in% names(tab))] <- "other"