如何使用 gsub() 准确替换字符串 [英] How do I replace the string exactly using gsub()

问题描述

我有一个语料库:txt =微电子图案中的图案层."我想用形式"完全替换术语模式"，我尝试编写代码:

I have a corpus: txt = "a patterned layer within a microelectronic pattern." I would like to replace the term "pattern" exactly by "form", I try to write a code:

txt_replaced = gsub("pattern","form",txt)

然而，txt_replaced 中的响应语料是:在微电子形式中形成的层."

However, the responsed corpus in txt_replaced is: "a formed layer within a microelectronic form."

如您所见，术语patterned"被错误地替换为formed"，因为patterned"中的部分特征与pattern"匹配.

As you can see, the term "patterned" is wrongly replaced by "formed" because parts of characteristics in "patterned" matched to "pattern".

我想查询是否可以使用 gsub() 准确替换字符串?即只替换完全匹配的词条.

I would like to query that if I can replace the string exactly using gsub()? That is, only the term with exactly match should be replaced.

我渴望得到如下回复:微电子形式中的图案层."

I thirst for a responsed as below: "a patterned layer within a microelectronic form."

非常感谢！

推荐答案

正如@koshke 所指出的，之前(由我)回答了一个非常相似的问题....但那是grep，这是gsub，所以我会再次回答:

As @koshke noted, a very similar question has been answered before (by me). ...But that was grep and this is gsub, so I'll answer it again:

"<"是单词开头的转义序列，">" 是结尾.在 R 字符串中，您需要将反斜杠加倍，因此:

"<" is an escape sequence for the beginning of a word, and ">" is the end. In R strings you need to double the backslashes, so:

txt <- "a patterned layer within a microelectronic pattern."
txt_replaced <- gsub("\<pattern\>","form",txt)
txt_replaced
# [1] "a patterned layer within a microelectronic form."

或者，您可以使用  而不是 < 和 >. 匹配一个词边界，所以它可以在两端使用>

Or, you could use  instead of < and >.  matches a word boundary so it can be used at both ends>

txt_replaced <- gsub("\bpattern\b","form",txt)

另请注意，如果您只想替换一次，则应使用 sub 而不是 gsub.

Also note that if you want to replace only ONE occurrence, you should use sub instead of gsub.

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