通过索引快速替换字符串中的多个字符 [英] Replace multiple characters, by index, in a string quickly

问题描述

我正在尝试用另一个字符(例如*

I'm trying to quickly replace multiple characters in a string with another character such as *

例如，我有一个字符串，例如:

For example, I have a string such as:

string = "abcdefghij"

我还有一个索引向量，指示我要在上面的字符串中用另一个字符替换字母的位置.

I also have a vector of indexes that indicate where I would like to replace letters in the above string with another character.

string_indexes_replaced = c(1, 4, 6, 9)

所需的输出:

"*bc*e*gh*j"

我做了什么

我尝试了一种非常新手的方法，例如将字符分成列表，用*替换字符，然后将列表折叠回所需的字符串，如下所示:

I've tried a very novice like approach of splitting the characters up into a list, replacing the characters with *, then collapsing the list back into the desired string, as shown below:

library(dplyr)
library(stringi)

string%>%
strsplit(split = "")%>%
lapply(function(x) replace(x, string_indexes_replaced, rep("*", length(string_indexes_replaced))))%>%
lapply(stri_flatten)%>%
unlist(use.names = FALSE)

输出

"*bc*e*gh*j"

但是很明显，应该有比我上面发布的更简单，更快速的东西.有没有更简单的&比我在这里展示的要快?

but it is clear that there should be something simpler and faster than what I've posted above. Is there anything simpler & quicker than what I've demonstrated here?

推荐答案

，除了

in base R, besides the method of substring() and for-loop shown by @akrun,, you can use utf8ToInt() and intToUtf8 to make it

v <- utf8ToInt(string)
v[string_indexes_replaced ] <- utf8ToInt("*")
res <- intToUtf8(v)

给出

> res
[1] "*bc*e*gh*j"

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