从字符串中删除特定的最后一个字符 [英] Remove specific last character from string

问题描述

我有以下字符串向量:

 EC02   502R   603           515    602   
 KL07   601    511R   505R   506R   503   
 508    514    501    509R   510    501R  
 512R   516    507    604    502    601R  
 SPK01  504    504R   ACK01  503R   508R  
 507R   ACK03  513    EC01   506    ECH01 
 ACK02  SPK02  509    511    512    505   
 KA01   RS01   510R   SKL01  SPK03  603R  
 602R   604R   513R   AECH01 ER03   AECH02
 RS02   514R   ER01   RH01   AR05   RH02  
 515R   ER02   M01 

我要替换502R to 502, 501R to 501, 503R to 503，依此类推...

I want to replace 502R to 502, 501R to 501, 503R to 503 and so on...

只有字符R必须替换，该字符出现在字符串的末尾.

Only character R has to be replaced which is occurring at the end of the string.

如何使用gsub做到这一点?

推荐答案

如果您有字符串矢量，并且想要替换其中的最后一个R字符，则可以使用sub. $在这里确保R是向量中的最后一个字符.

If you have a string vector and want to replace the last R character from it you can use sub. $ here ensures that the R is the last character in your vector.

sub("R$", "", str)

#[1] "EC02"  "502"   "603"   "5RFRS"

数据

str <- c("EC02", "502R","603", "5RFRS)

我在这里使用的是sub而不是gsub. sub仅替换第一次出现的模式，而gsub替换所有出现的模式，尽管在这种情况下sub/gsub的使用无关紧要.

I have used sub here instead of gsub. sub replaces only first occurrence of the pattern whereas gsub replaces all occurrences of the pattern though in this case the usage of sub/gsub wouldn't matter.

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