gsub()可以用于字段的删减、增补、替换和切割，可以处理一个字段也可以处理由字段组成的向量。
具体的使用方法为：gsub("目标字符", "替换字符", 对象)
在gsub函数中，任何字段处理都由将“替换字符”替换到“目标字符”这一流程中实现，令替换字符为''''可实现删除，令替换字符为"目标字符+增补内容"可实现增补，替换和切割也是使用类似的操作。
|
1
2
3
|
> text <- "AbcdEfgh . Ijkl MNM"> gsub("Efg", "AAA", text) #将Efg改为AAA，区分大小写[1] "AbcdAAAh . Ijkl MNM" |
任何符号，包括空格、Tab和换行都是可以识别的
|
1
2
|
> gsub(" I", "i", text) #可识别空格[1] "AbcdEfgh .ijkl MNM" |
同时字符可以识别多个，进行批量置换
|
1
2
|
> gsub("M", "N", text) [1] "AbcdEfgh . Ijkl NNN" |
除此之外，gsub还有其他批量操作的方法
|
1
2
3
4
5
6
7
8
|
> gsub("^.* ", "a", text) #开头直到最后一个空格结束替换成a[1] "aMNM"> gsub("^.* I(j).*$", "\\1", text) #只保留一个j[1] "j"> gsub(" .*$", "b", text) #第一个空格直达结尾替换成b[1] "AbcdEfghb"> gsub("\\.", "\\+", text) #句号.和加号+是特殊的，要添加\\来识别[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 |
到此这篇关于R语言gsub替换字符工具的具体使用的文章就介绍到这了,更多相关R语言gsub替换字符工具内容请搜索服务器之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持服务器之家！
原文链接：https://blog.csdn.net/lztttao/article/details/82086346
