将所有因子列转换为data.frame中的字符,而不会影响非因子列

Question

例如,我有一个包含整数列和因子列的data.frame.

data <- data.frame(
    a = 1:5, 
    b = factor(c("a", "b", "c", "d", "e")), 
    c = factor(c("f", "g", "h", "i", "j")))`

我想将b和c因子列转换为字符,并将列a保持为整数.

我尝试了以下代码:

sapply(data, function(x) {if_else(is.factor(x), as.character(x), x)})

它没有得到结果,而是抛出一个错误:

错误:true必须是长度1(长度condition),而不是5

我知道这可以通过dplyr中的mutate_if函数来完成.但我仍然想知道为什么我的代码不能用于这种情况.

非常感谢您的任何建议!

Answer 1

你可以试试:

library(tidyverse)
d <- data.frame(a = 1:5, 
                b = factor(c("a", "b", "c", "d", "e")), 
                c = factor(c("f", "g", "h", "i", "j")))
d %>% glimpse() 
Observations: 5
Variables: 3
$ a <int> 1, 2, 3, 4, 5
$ b <fctr> a, b, c, d, e
$ c <fctr> f, g, h, i, j

d %>% 
  mutate_if(is.factor, as.character) %>% 
  glimpse()
Observations: 5
Variables: 3
$ a <int> 1, 2, 3, 4, 5
$ b <chr> "a", "b", "c", "d", "e"
$ c <chr> "f", "g", "h", "i", "j"

使用base R你可以试试

d[] <- lapply(d, function(x) if(is.factor(x)) as.character(x) else x)