R-多条件summarize_if

Question

我试图将观察的df简化为单个观察(单行)。我希望summarize_if是数字的平均值，如果是字符串或因子的模式。下面的代码不起作用，但我希望它能给出这个想法。谢谢!

#data frame
num <- c(1:7)
str <- c("toy","control","play",NA,"give","toy","toy")
df_finale <- data.frame(num,str)

#mode function
Mode <- function(x) {
        ux <- unique(x)
        ux[which.max(tabulate(match(x, ux)))]
}

#df reduction
df_finale <- df_finale %>%
                    summarize_if(is.numeric, mean, na.rm = TRUE) %>%
                    summarize_else_if(!is.numeric, Mode)

Answer 1

一种可能是：

df_finale %>%
 summarise_all(~ if(is.numeric(.)) mean(., na.rm = TRUE) else Mode(.))

  num str
1   4 toy

或者是一个选项，因为dplyr 1.0.0

df_finale %>%
 summarise(across(everything(), ~ if(is.numeric(.)) mean(., na.rm = TRUE) else Mode(.)))

Answer 2

我们可以用mutate_if和distinct

library(dplyr)
library(purrr)
df_finale %>%
     mutate_if(is.numeric, mean, na.rm = TRUE) %>% 
     mutate_if(negate(is.numeric), Mode) %>%
     distinct
#   num str
#1   4 toy

或者使用新版本的across/summarise的dplyr

i1 <- df_finale %>% 
           summarise_all(is.numeric) %>%
           flatten_lgl

df_finale %>% 
     summarise(across(names(.)[i1], ~ mean(., na.rm = TRUE)), 
               across(names(.)[!i1], Mode))