是否有运算符可以简化C＃中的此操作以避免空指针异常？
obj == null ? null : obj.Property;
类似
obj?.Property;
我真的想摆脱NullReferenceExeptions
答案 0 :(得分：1)
正如@ canton7所说，您回答了自己的问题。
library(dplyr)
setregion <- function(uf) {
region_out <- case_when(
uf %in% c("RO","AC","AM","RR","PA","AP","TO") ~ "North",
uf %in% c("MA","PI","CE","RN","PB","PE","AL","SE","BA") ~ "Northeast",
uf %in% c("MG","ES","RJ","SP") ~ "Southeast",
uf %in% c("PR", "SC", "RS") ~ "South",
uf %in% c("MS","MT","GO", "DF") ~ "Midwest"
)
return(region_out)
}
运算符实际上在C＃中存在
下面是一个小示例，展示了它如何防止?.
NullReferenceException