我怎样才能只替换某些位置的文本,例如(“披头士”或“披头士,THE”)

你可以用锚 ^ 和 $ 指示每个字符串的开头和结尾。也可以将阵列组与 | 只使用一种模式,并且可以使用便利功能 str_remove() str_replace(replacement = "") . 这些是 正则表达式 here

library(tidyverse)
df <- data.frame(
  stringsAsFactors = FALSE,
  Name = c(
    "The Beatles", "Rolling Stones, The", "Puff The Magic Dragon",
    "The Offspring"
  ),
  Number = c(100L, 100L, 100L, 100L)
)
df %>%
  mutate(Name = str_remove_all(Name, "(^The )|(, The$)"))
#>                    Name Number
#> 1               Beatles    100
#> 2        Rolling Stones    100
#> 3 Puff The Magic Dragon    100
#> 4             Offspring    100

^{于2019-03-14由 reprex package}

sub

sub("^The |, The$", "", df$Name)

#[1] "Beatles"   "Rolling Stones"  "Puff The Magic Dragon" "Offspring"  

或与 str_replace

library(tidyverse)

df %>%
  mutate(Name = str_replace(Name, "^The |, The$", ""))

#                   Name Number
#1               Beatles    100
#2        Rolling Stones    100
#3 Puff The Magic Dragon    100
#4             Offspring    100