如何在 Golang 中使用正则表达式拆分文本？

什么是正则表达式？正则表达式是著名的动漫字符吗？哎呀，如果你这么想，你很可能会失望。 Go 编程语言使用术语regexp来表示正则表达式。正则表达式在字符串处理领域非常重要。 Go 中的“ regexp ”包包含所有必要的预构建函数，这些函数实现正则表达式搜索，并保证在提供的输入大小上进行线性时间搜索。要了解有关正则表达式的更多信息，请阅读Golang 中的正则表达式是什么？

如何使用正则表达式（或正则表达式）分割输入文本？

Regexp 包包含 Split函数，它有助于拆分输入文本字符串。在我们深入了解 regexp split函数，让我们向您简要介绍一些在使用 split函数值得记住的基本正则表达式：

Character(s)	What it signifies?	Example syntax	Result of regex
[ ]	[ ] Can be used for including or  excluding a given range, or even  mention specifically the characters  that we want to include or exclude.  [ ] means both inclusive in a range.	“[b-f]an”	ban, can, dan, ean, fan
{ }	The curly brackets are used when  one needs to match the frequency  of the occurrence of any given   expression.	“gf{1,}g”	gfg, gffg, gfffg,…
( )	( ) Can be used for including or  excluding a given range, or even  mention specifically the  characters that we want to  include or exclude. ( ) means  numbered capturing group.	“(b-f)an”	ban, can, dan, ean, fan
*	* Matches 0/0+ occurrences  of the character that precedes  the star (‘*’).	“gee*k”	gek, geek, geeek…
+	+ Matches 1/1+ occurrences  of the character that precedes  the plus (‘+’).	“gee+k”	geek, geeek,…
?	? Matches 0 & 1 occurrences  of the character that precedes  the question mark (‘?’).	“gee?k”	gek, geek
.	Anything can replace the dot  character, except a newline (\n).	“g.g”	gfg, gbg, gcg,…
^	Any text that starts with the string  mentioned after ‘^’.  Also used as a negation in groups  or other regular expressions (NOT).	“^ge” “[^0-8]*”	ge, geek, geeks,… ‘ ‘,9, 99,999,…
$	It denotes the end of the string in a   single-lined text and the end of a  line in a multi-line text.	“$de”	code, decode,…
|	| is the or operator.	“geek|principle”	geek, geeks, principle, principles..
\	This is the escape character  If you need to mention anything  like ‘\s’ then you need to  use ‘ \\s’ so that the system  understands that it is ‘\s’.	“\A” “\\n” “\\s”  etc..
\s	Extracts all white spaces only	“\\s”	” “, ”  “, ”   “,…
\S	Extracts all text except white spaces	“\\S”
\d	Extracts all digits only	“\\d”	0, 1, 2, 3, 4, 5, 6, 7, 8, 9
\D	Extracts all text except digits	“\\D”

句法：

func Split(s: string, n: int) []string

此函数接受一个字符串和一个整数，并返回所有子字符串的切片。输入字符串的‘是将进一步，分裂是成子按照由Split函数给定正则表达式的字符串。 ‘ n ‘ 表示决定要返回的子串数量的值。

• 如果n > 0 ：表示最多有 n 个子串进行正则运算并返回。
• 如果n = 1则不执行正则表达式操作，因此将返回原始字符串。
• 如果n = 0 ：表示不返回子字符串，应返回 nill。
• 如果n < 0 ：表示创建的所有子串都将由函数返回。

示例 1：

Go

package main
  
import (
    f "fmt"
    re "regexp"
    // we import the regexp package
    // as re
)
  
// SPLIT function hacks
// In layman terms, whenever the
// string (given to split as argument)
// occurs, the string is split into
// a substring.
  
func main() {
  
    // str stores a sample string as shown below
    str := "I am at GFG!\nYou can call me at 9087651234."
      
    // just printing the original string: str
    f.Println(str)
  
    // We shall consider two scenarios
    // in this example code
  
    // Scenario 1:
    // Store a regex object that
    // contains digits only
    // in obj1.
    obj1 := re.MustCompile("\\d*")
  
    // Scenario 2:
    // Store a regex object that
    // contains everything except digits
    // in obj2.
    obj2 := re.MustCompile("\\D*")
  
    // Using obj1 as reference, we
    // are splitting the string: str
    // and -1 denotes that all substrings
    // ever created will be included.
    first := obj1.Split(str, -1)
      
    // "first" holds all the substrings
    // split from str w.r.t obj1 in a container
    // A container like, say a list.
  
    // Using obj2 as reference, we
    // are splitting the string: str
    // and -1 denotes that all substrings
    // ever created will be included.
    second := obj2.Split(str, -1)
    // "second" holds all the substrings
    // split from str w.r.t obj2 in a container
    // A container like, say a list.
  
    f.Println("Now printing text split by obj1...")
    for _, p := range first {
        f.Println(p)
    }
  
    f.Println("Now printing text split by obj2...")
    for _, q := range second {
        f.Println(q)
    }
}

执行命令：

> go run (your_file_name).go

输出：

I am at GFG!
You can call me at 9087651234.
Now printing text split by obj1...
I

a
m

a
t

G
F
G
!


Y
o
u

c
a
n

c
a
l
l

m
e

a
t

.
Now printing text split by obj2...

9
0
8
7
6
5
1
2
3
4

Visual Studio Code 上的 Visual I/O 演示：

运行上面编写的代码时在屏幕上输出代码。

示例 2：

去

package main
  
import (
    f "fmt"
    re "regexp"
)
  
// Simple example code to understand
// 1. Function of Split function
// 2. Parameters of split function
// regex-object.Split(string: , n: )
  
func main() {
  
    // Sample string that will be used in this
    // example "GeeksforGeeks loves bananas"
    str := "GeeksforGeeks loves bananas"
    f.Println(str)
  
    f.Println("Part-1: Excluding all vowels from given string")
      
    // a regexp object (geek) for storing all vowels
    geek := re.MustCompile("[aeiou]")
    f.Print("Printing all substring lists = ")
      
    // Checking split for n = -1
    f.Println(geek.Split(str, -1))
    f.Print("For n = 0 substring list = ")
      
    // Checking split for n = 0
    f.Println(geek.Split(str, 0))
    f.Print("For n = 1 substring list = ")
      
    // Checking split for n = 1
    f.Println(geek.Split(str, 1))
    f.Print("For n = 10 substring list = ")
      
    // Checking split for n = 10
    f.Println(geek.Split(str, 10))
    f.Print("For n = 100 substring list = ")
      
    // Checking split for n = 100
    f.Println(geek.Split(str, 100))
  
    f.Println("\n\nPart-2: Extracting all vowels from given string")
      
    // a regexp object (geek) for storing all consonants
    geek = re.MustCompile("[^aeiou]")
      
    f.Print("Printing all substring lists = ")
      
    // Checking split for n = -1
    f.Println(geek.Split(str, -1))
    f.Print("For n = 0 substring list = ")
      
    // Checking split for n = 0
    f.Println(geek.Split(str, 0))
    f.Print("For n = 1 substring list = ")
      
    // Checking split for n = 1
    f.Println(geek.Split(str, 1))
    f.Print("For n = 10 substring list = ")
      
    // Checking split for n = 10
    f.Println(geek.Split(str, 10))
    f.Print("For n = 100 substring list = ")
      
    // Checking split for n = 100
    f.Println(geek.Split(str, 100))
  
    // Did you notice that split function
    // does not modify the original regex
    // matching object?
}

执行命令：

> go run (your_file_name).go

输出：

GeeksforGeeks loves bananas
Part-1: Excluding all vowels from given string
Printing all substring lists = [G  ksf rG  ks l v s b n n s]
For n = 0 substring list = []
For n = 1 substring list = [GeeksforGeeks loves bananas]
For n = 10 substring list = [G  ksf rG  ks l v s b n nas]
For n = 100 substring list = [G  ksf rG  ks l v s b n n s]


Part-2: Extracting all vowels from given string
Printing all substring lists = [ ee   o  ee    o e   a a a ]
For n = 0 substring list = []
For n = 1 substring list = [GeeksforGeeks loves bananas]
For n = 10 substring list = [ ee   o  ee   loves bananas]
For n = 100 substring list = [ ee   o  ee    o e   a a a ]

Visual Studio Code 上的 Visual I/O 演示：

运行上面编写的代码时在屏幕上输出代码。