R ifelse 语句只返回数字

Question

这是 house$room

type<-c('2?1?','2?2?','3?2?','1?1?','4?2?',
        '3?1?','1?','2?','1?2?','5?2?','4?3?')

为什么ifelse只返回数字？

Answer 1

这可能是因为house$room是factor它被裹挟到integer了内存储的值ifelse循环。一种选择是转换为character类

ifelse(house$room %in% type, as.character(house$room), '??????')