将 map_dbl 输出转换为 R tidyverse 中的 tibble

Question

我在 R 中处理大量数据帧，我想找到具有最小和最大列数的数据帧，并找出它们的列名的差异。但是，我无法将我的 map_dbl 结果变成常规的 tibble。

first_df   = data.frame(matrix(rnorm(20), nrow=10))
second_df  = data.frame(matrix(rnorm(20), nrow=4))
third_df   = data.frame(matrix(rnorm(20), nrow=5))

library(dplyr)
library(purrr)
library(tibble)
library(tidyr)

# capturing all the data frames
mget(ls(pattern = "_df"))  %>% 
map_dbl(ncol)      %>% 
as_tibble() 


# expected output
# first_df   2
# second_df  5

## Finding the difference in columns
diff <- setdiff(colnames(first_df), colnames(second_df ))

Answer 1

你可以这样做：

library(tidyverse)

min_max <- mget(ls(pattern = "_df")) %>%
  map_dbl(ncol) %>%
  enframe() %>%
  arrange(value) %>%
  slice(1, n())

min_max

# A tibble: 2 x 2
#  name      value
#  <chr>     <dbl>
#1 first_df      2
#2 second_df     5

setdiff(names(get(min_max$name[2])), names(get(min_max$name[1])))
#[1] "X3" "X4" "X5"

将 map_dbl 输出转换为 R tidyverse 中的 tibble

converting map_dbl output to tibble in R tidyverse

r

list

purrr