Question

非常简单的问题，但我很难找到解决方案。

想要离开：

a = c("the sky is color", "the color dog", "grass is color") 
b = c("blue","brown","green") 
df = data.frame(a,b)

对此：

a = c("the sky is color", "the color dog", "grass is color") 
b = c("blue","brown","green") 
c = c("the sky is blue", "the brown dog", "grass is green")
df = data.frame(a,b,c)

尝试使用gsub：

df$d <- gsub('color', df$b, df$a)

但收到此错误消息：

argument 'replacement' has length > 1 and only the first element will be used

该解决方案是否也适用于整数？谢谢！

Answer 1

我认为这是一个简洁的矢量化解决方案，但您可以使用简单的apply语句来完成它。

a = c("the sky is color", "the color dog", "grass is color") 
b = c("blue","brown","green") 
df = data.frame(a,b) 

df$d <- apply(df,1,function(x){gsub('color', x[2], x[1])})


df$d

[1]＆＃34;天空是蓝色的＆＃34; ＆＃34;棕色的狗＆＃34; ＆＃34;草是绿色的＆＃34;

Answer 2

stringi包中的大多数函数都是矢量化的，所以你可以这样做

df$c <- stringi::stri_replace_all_fixed(df$a, 'color', df$b)

df
##                  a     b               c
## 1 the sky is color  blue the sky is blue
## 2    the color dog brown   the brown dog
## 3   grass is color green  grass is green

如果您愿意，可以在dplyr或data.table中实现。

Answer 3

我们可以使用mapply

df$a <- mapply(sub, 'color', df$b, df$a)
df$a
#[1] "the sky is blue" "the brown dog"   "grass is green"

或者我们可以使用str_replace_all

中的stringr

library(stringr)
df$a <- str_replace_all(df$a, 'color', df$b)
df$a
#[1] "the sky is blue" "the brown dog"   "grass is green"

或使用tidyverse

library(dplyr)
df %>%
    mutate(a = str_replace_all(a, 'color', b))

Answer 4

有Vectorize函数可以让你指定一些矢量化参数。在这种情况下，您希望对“替换”参数和名为“x”的字符串参数进行矢量化：

(df$c <- Vectorize(gsub, c("replacement", "x"))("color", df$b, df$a, fixed = TRUE))
# [1] "the sky is blue" "the brown dog"   "grass is green"

变量替换 - R.

4 个答案: