我试图从一个列表（有一个类似日期的字符列）中对几个 Dataframe 进行过滤。
我知道我所有的df都有n个（这里是10个）实体，然后我试图找出long_df格式，其中每行都是一对实体-日期。
然后我想在这些长df上应用一个过滤函数，找到是日期的字符列，只保留一年。
我听说filter_if已经过时了，所以我尝试过跨语法使用它，但到目前为止失败了。
你知道为什么它不工作吗？

## a list of df 

list_df <- list(A = data.frame(ID = letters[1:10],
                               Var1 = rnorm(10),
                               Var2 = rnorm(10),
                               Var3 = rnorm(10)),
                B = data.frame(ID = rep(letters[1:10],3),
                               X = c(rep("01/01/2018", 10), 
                                     rep("01/01/2019", 10),
                                     rep("01/01/2020", 10)),
                               Var1 = rnorm(30),
                               Var2 = rnorm(30)),
                C = data.frame(ID = rep(letters[1:10],2),
                               D = c(rep("01/01/2018", 10), 
                                     rep("01/01/2019", 10)),
                               Var1 = rnorm(20),
                               Var2 = rnorm(20)))

## a custom function to find character column that are date (= B$X & C$D)

guessdate <- function(x) !all(is.na(as.Date(as.character(x),format="%d/%m/%Y"))) 

#test the function on one df
list_df[["B"]] %>% map(., guessdate)

## what i've tried so far
list_df %>% map_if(.p = ~ nrow(.x) > 10,  # apply function only on dataframe with more than 10 rows
                          ~ filter(across(where(map(., guessdate)), ~ str_detect(.x, "2018")))) ## filter the date-like column keeping only (2018) 

## desired ouput

output <- list(A = data.frame(ID = letters[1:10],
                               Var1 = rnorm(10),
                               Var2 = rnorm(10),
                               Var3 = rnorm(10)),
                B = data.frame(ID = letters[1:10],
                               X = c(rep("01/01/2018", 10)),
                               Var1 = rnorm(10),
                               Var2 = rnorm(10)),
                C = data.frame(ID = letters[1:10],
                               D = c(rep("01/01/2018", 10)),
                               Var1 = rnorm(10),
                               Var2 = rnorm(10)))