在R中使用case_w时获取NA

Question

我正试图用各自的城市来掩盖NFL球队。当我尝试获取NA时，尝试使用case_。下面是代码

nfl_RM %>% 
  select(team_name) %>% 
  mutate(state = case_when(
                           team_name %in% c("Rams","Chargers","49ers","Raiders") ~ "California", 
                           team_name %in% c("Jaguars", "Dolphins", "Buccaneers") ~ "Florida",
                           team_name %in% c("Ravens","Redskins") ~ "Maryland",
                           team_name == "Cardinals" ~ "Arizona",
                           team_name %in% c("Eagles","Steelers") ~ "Pennsylvania",
                           team_name %in% c("Bengals","Browns") ~ "Georgia",
                           team_name %in% c("Jets","Giants") ~ "New Jersey",
                           team_name %in% c("Cowboys","Texans") ~ "Texas",
                           team_name == "Broncos" ~ "Colorado",
                           team_name == "Falcons" ~ "Georgia",
                           team_name == "Bears" ~ "Illinois",
                           team_name == "Colts" ~ "Indiana",
                           team_name == "Saints" ~ "Louisiana",
                           team_name == "Patriots" ~ "Massachusetts",
                           team_name == "Lions" ~ "Michigan",
                           team_name == "Vikings" ~ "Minnesota",
                           team_name == "Chiefs" ~ "Missouri",
                           team_name == "Bills" ~ "New York",
                           team_name == "North Carolina" ~ "Panthers",
                           team_name == "Titans" ~ "Tennessee",
                           team_name == "Seahawks" ~ "Washington",
                           team_name == "Packers" ~ "Wisconsin"
                           )
         )

输出

team_name state

"Lions"     NA          
"Lions"     NA          
"Lions"     NA          
"Lions"     NA          
"Lions"     NA          
"Packers"   NA

还有，还有其他方法吗？

Answer 1

[可能是数据集中已经有NA，而==为这些返回了NA，或者字符串不完全匹配。在这种情况下，我们可能需要str_detect来匹配子字符串

一个更好的选择是创建一个键/值数据集，然后执行一个left_join而不是100的case_when

library(dplyr)
keyval <- data.frame(team_name = c("Lions", "Tigers",  "Deers"),
       state = c("Michigan", "Minnesota", "Kansas"), stringsAsFactors = FALSE)

nfl_RM %>% 
   select(team_name) %>%
   left_join(keyval)