R에러 코드

View(welfare)
View(list_job)
table(is.na(welfare$code_job))
left_join(welfare,list_job,by="code_job")

welfare <- welfare %>%
  mutate(left_join(welfare,list_job,by="code_job"))

## job컬럼을 기준으로 평균 월급을 출력 

welfare %>% filter(!is.na(welfare$code_job)) %>%
  group_by(welfare$code_job) %>% 
  summarise(income_mean = mean(income))

[Errorcode]