r - 修改字符串后如何重置向量的因子？

Question

修改字符串后如何重置向量的因子/水平？

library(stringr)
x <- c("  x1", "x1", "x2 ", " x2", "x1 ", "x2") # Whitespace left or right
as.character(x)
[1] "  x1" "x1"   "x2 "  " x2"  "x1 "  "x2" 
str_replace_all(x, fixed(" "), "")
[1] "x1" "x1" "x2" "x2" "x1" "x2"
factor(x)
[1]   x1 x1   x2    x2  x1   x2
Levels: x1  x2 x1 x1  x2 x2`

我想要这样的结果:

[1] x1 x1 x2 x2 x1 x2
Levels:   x1  x2

Answer 1

此操作不需要任何软件包。你可以做

factor(trimws(x))
# [1] x1 x1 x2 x2 x1 x2
# Levels: x1 x2

trimws() 用于修剪空白，并且在基本 R (>= 3.2.0) 中可用。