在 R 中查找并替换整个值 [英] Find and replace entire value in R

问题描述

我正在寻找一种方法来使用 R 中的查找和替换函数来替换字符串的整个值，而不仅仅是字符串的匹配部分.我有一个包含很多(非常)长名称的数据集，我正在寻找一种有效的方法来查找和更改它们的值.

I'm looking for a way to use the find and replace function in R to replace the entire value of a string, rather than just the matching part of the string. I have a dataset with a lot of (very) long names, and I'm looking for an efficient way to find and change their values.

例如，我尝试更改整个字符串

So, for instance, I tried to change this entire string

string <- "Generally.speaking..do.you.prefer.to.try.out.new.experiences.like.trying.things.and.meeting.new.people..or.do.you.prefer.familiar.situations.and.faces."

到

"exp"

使用此代码

string <- gsub("experiences", "exp", string)

然而，这会导致仅用匹配experiences"的字符串部分替换exp"，并且保留长名称的其余部分完整(为清晰起见加粗):

However, this results in substituting "exp" with only the part of string that matches "experiences", and it leaves the rest of the long name intact (bolded for clarity):

一般来说.speaking..do.you.prefer.to.try.out.new.exp..like.trying.things.and.meeting.new.people..or.do.you.prefer.familiar.situations.and.faces."

"Generally.speaking..do.you.prefer.to.try.out.new.exp..like.trying.things.and.meeting.new.people..or.do.you.prefer.familiar.situations.and.faces."

在这种情况下，由于字符串包含experiences"，因此应将其替换为exp".

In this case, because the string contains "experiences", it should be replaced with "exp."

有没有办法告诉 gsub 或其他一些函数来替换整个值?我看了很多教程，似乎函数只能在字符串内或整个值上运行，而不能在两者之间运行.

Is there a way to tell gsub or some other function to replace the entire value? I looked a lot of tutorials and it seems like functions only operate within a string or on whole values, but not between the two.

推荐答案

您可以使用 gsub 如下:

 gsub(".*experiences.*", "exp", string, perl=TRUE) 
 # As @rawr notes, set perl=TRUE for improved efficiency

此正则表达式匹配包含任何字符 0 次或多次(即 .*)后跟experiences"，后跟任何字符 0 次或多次的字符串.

This regex matches strings that have any characters 0 or more times (i.e. .*) followed by "experiences", followed by any characters 0 or more times.

在这种情况下，您仍然用exp"替换整个匹配，但是通过使用正则表达式，您可以扩展匹配的定义(从experience"到.*experience.*")以实现所需的替换.

In this case, you are still replacing the entire match with "exp" but by using regex, you expand the definition of the match (from "experience" to ".*experience.*") to achieve the desired substitution.

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