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R語言gsub替換字符工具的具體使用

更新時(shí)間：2021年03月11日 09:30:15 作者：lztttao

這篇文章主要介紹了R語言gsub替換字符工具的具體使用，文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧

gsub()可以用于字段的刪減、增補(bǔ)、替換和切割，可以處理一個(gè)字段也可以處理由字段組成的向量。

具體的使用方法為：gsub("目標(biāo)字符", "替換字符", 對(duì)象)

在gsub函數(shù)中，任何字段處理都由將“替換字符”替換到“目標(biāo)字符”這一流程中實(shí)現(xiàn)，令替換字符為''''可實(shí)現(xiàn)刪除，令替換字符為"目標(biāo)字符+增補(bǔ)內(nèi)容"可實(shí)現(xiàn)增補(bǔ)，替換和切割也是使用類似的操作。

> text <- "AbcdEfgh . Ijkl MNM"
> gsub("Efg", "AAA", text) #將Efg改為AAA，區(qū)分大小寫
[1] "AbcdAAAh . Ijkl MNM"

任何符號(hào)，包括空格、Tab和換行都是可以識(shí)別的

> gsub(" I", "i", text)  #可識(shí)別空格
[1] "AbcdEfgh .ijkl MNM"

同時(shí)字符可以識(shí)別多個(gè)，進(jìn)行批量置換

> gsub("M", "N", text) 
[1] "AbcdEfgh . Ijkl NNN"

除此之外，gsub還有其他批量操作的方法

> gsub("^.* ", "a", text) #開頭直到最后一個(gè)空格結(jié)束替換成a
[1] "aMNM"
> gsub("^.* I(j).*$", "\\1", text) #只保留一個(gè)j
[1] "j"
> gsub(" .*$", "b", text) #第一個(gè)空格直達(dá)結(jié)尾替換成b
[1] "AbcdEfghb"
> gsub("\\.", "\\+", text) #句號(hào).和加號(hào)+是特殊的，要添加\\來識(shí)別
[1] "AbcdEfgh + Ijkl MNM"

Syntax	Description
\\d	Digit, 0,1,2 ... 9
\\D	Not Digit
\\s	Space
\\S	Not Space
\\w	Word
\\W	Not Word
\\t	Tab
\\n	New line
^	Beginning of the string
$	End of the string
\	Escape special characters, e.g. \\ is "\", \+ is "+"
\|	Alternation match. e.g. /(e\|d)n/ matches "en" and "dn"
•	Any character, except \n or line terminator
[ab]	a or b
[^ab]	Any character except a and b
[0-9]	All Digit
[A-Z]	All uppercase A to Z letters
[a-z]	All lowercase a to z letters
[A-z]	All Uppercase and lowercase a to z letters
i+	i at least one time
i*	i zero or more times
i?	i zero or 1 time
i{n}	i occurs n times in sequence
i{n1,n2}	i occurs n1 - n2 times in sequence
i{n1,n2}?	non greedy match, see above example
i{n,}	i occures >= n times
[:alnum:]	Alphanumeric characters: [:alpha:] and [:digit:]
[:alpha:]	Alphabetic characters: [:lower:] and [:upper:]
[:blank:]	Blank characters: e.g. space, tab
[:cntrl:]	Control characters
[:digit:]	Digits: 0 1 2 3 4 5 6 7 8 9
[:graph:]	Graphical characters: [:alnum:] and [:punct:]
[:lower:]	Lower-case letters in the current locale
[:print:]	Printable characters: [:alnum:], [:punct:] and space
[:punct:]	Punctuation character: ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { \| } ~
[:space:]	Space characters: tab, newline, vertical tab, form feed, carriage return, space
[:upper:]	Upper-case letters in the current locale
[:xdigit:]	Hexadecimal digits: 0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f