Select variables/columns 由具有匹配给定因子水平的那些人在数据框中

Question

可能 select 数据框中的变量与某些因子水平相匹配，select根据它们的因子水平（已使用或未使用）编辑列？我可以 summarise by levels or subset possibly by rows，但我想知道是否可以从数据框中 select 编辑列，或者至少列出 variables/columns，它们具有特定的因子水平。

library(dplyr)
height <- c(132,151,162,139,166,147,122)
    weight <- c(48,49,66,53,67,52,40)
    gender <- c("male","male","female","female","male","female","male")
    gender2 <- c("female","male","male","male","male","female","male")
    genderx <- c("xfemale","malex","malex","male","male","xfemale","xfemale")


    df <- data.frame(height,weight,gender, gender2, genderx) %>% 
      rowid_to_column(., "ID")

有点像（或不像）

%>% select (vars(levels ==(c("male", "female")))

Answer 1

我们可以使用select_if

library(dplyr)
df %>% 
    select_if(~ is.factor(.) && all(c("male", "female") %in% levels(.)))

也可以是any

df %>% 
    select_if(~ is.factor(.) && any(c("male", "female") %in% levels(.)))

Select variables/columns 由具有匹配给定因子水平的那些人在数据框中

Select variables/columns in a dataframe by those with matching given factor levels

select

r

levels

dataframe