Linux Shell 正则表达式

赵智松 發表於 2023-12-3 00:00:00

<div id="navCategory"><h5 class="catalogue">目录</h5><ul class="first_class_ul"><li>
简介<ul class="second_class_ul"><li>
常用字符</li><li>
普通字符</li><li>
限定符 </li><li>
定位符 </li><li>
分组 </li><li>
捕获分组</li><li>
非捕获分组</li><li>
反向引用 </li></ul></li></ul></div>
<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/76eb99f2514ad55567ea9fd47b319c74.jpg" width="auto">

<h2>
简介</h2>

正则表达式(regular expression)描述了一种字符串匹配的模式（pattern），可以用来检查一个串是否含有某种子串、将匹配的子串替换或者从某个串中取出符合某个条件的子串等。

常用正则表达式

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/ceb2ff713cb62adda13b14087169e427.jpg" width="auto">
<h3>
常用字符</h3>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/9a6ee3cbe362b8dd0b942f5f9e6ea506.jpg" width="auto">

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/6231f3b07e16cbc919dda650568e5962.jpg" width="auto">

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/fab8279cfd574700b190b10aec2be025.jpg" width="auto">

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/5fc85c8e192f13ed87f620cb52abd265.jpg" width="auto">
<h3>
普通字符</h3>

普通字符主要讲解以下内容，并举例说明
<ol class="dp-xml">
<li class="alt">
// String regStr = "";//匹配a-z中任意一个字符 
</li>
<li class="alt">
// String regStr = "";//匹配A-Z中任何一个字符 
</li>
<li class="alt">
// String regStr = "abc";//匹配字符串abc 
</li>
<li class="alt">
// String regStr = "(?i)abc";//匹配字母abc不区分大小写 
</li>
<li class="alt">
// String regStr = "";//匹配0-9任何一个字符 
</li>
<li class="alt">
// String regStr = "[^0-9]";//匹配不是0-9中的任何一个字符 
</li>
<li class="alt">
// String regStr = "[^0-9]{2}";//匹配2个不是0-9的字符 
</li>
<li class="alt">
// String regStr = "\\d";//匹配任何一个数字字符，等价于 
</li>
<li class="alt">
// String regStr = "\\D";//匹配任何一个非数字字符，等价于[^0-9] 
</li>
<li class="alt">
// String regStr = "\\w";//匹配任何一个数字、字母、下划线，等价于 
</li>
<li class="alt">
// String regStr = "\\W";//匹配任何一个除了数字、字母、下划线，等价于[^0-9a-zA-Z_] 
</li>
<li class="alt">
// String regStr = "\\s";//匹配任何一个空字符 
</li>
<li class="alt">
// String regStr = "\\S";//匹配任何一个非空字符 
</li>
<li class="alt">
// String regStr = "ab|cd";//选择匹配符，匹配字符串ab或者cd 
</li>
</ol>

1) String regStr = "";//匹配a-z中任意一个字符
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test1() { 
</li>
<li class="alt">
 String str = "abc2021"; 
</li>
<li class="alt">
 String regStr = ""; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
 } 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/186ed9887e8af7e3ff8362f4992e2449.jpg" width="auto">

结果展示

2) String regStr = "";//匹配A-Z中任何一个字符
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "ABCabc2021"; 
</li>
<li class="alt">
 String regStr = ""; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/2999a8ba90a257782a1e17991dd222cd.jpg" width="auto">

结果展示

3）String regStr = "abc";//匹配字符串abc
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "ABCabc2021"; 
</li>
<li class="alt">
 String regStr = "abc"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/cf680f58f66f04c76dc3a490db9a3fbc.jpg" width="auto">

结果展示

4）String regStr = "(?i)abc";//匹配字母abc不区分大小写
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "ABCabc2021"; 
</li>
<li class="alt">
 String regStr = "(?i)abc"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/a6a62ccdc73e07cec17b7ce0f2e08068.jpg" width="auto">

结果展示

5） String regStr = "";//匹配0-9任何一个字符
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "ABCabc2021"; 
</li>
<li class="alt">
 String regStr = ""; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/aeb3d077954626c4ded87a022d3d1f25.jpg" width="auto">

结果展示

6） String regStr = "[^0-9]";//匹配不是0-9中的任何一个字符
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "ABCabc2021"; 
</li>
<li class="alt">
 String regStr = "[^0-9]"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/4b9554c497f4c2f242e16948d820f83b.jpg" width="auto">

结果展示
<h3>
限定符 </h3>
<ol class="dp-xml">
<li class="alt">
/** 
</li>
<li class="alt">
 * 限定符 
</li>
<li class="alt">
 * *：表示出现任意次数，0次或者n次，如（abc)*表示abc出现0次或者多次 
</li>
<li class="alt">
 * +：表示出现至少1次或者n次，如（abc)+表示abc出现1次或者多次 
</li>
<li class="alt">
 * ？：表示出现至少0次或者1次，如abc？表示c出现0次或者1次 
</li>
<li class="alt">
 * {n}:表示出现n次，如{2},表示匹配2次数字 
</li>
<li class="alt">
 * {n,}表示至少出现n次，如{3,}表示匹配至少3次数字 
</li>
<li class="alt">
 * {n,m}表示出现至少n次，最多m次，如{2,4}表示匹配次数2-4次数字 
</li>
<li class="alt">
 */ 
</li>
</ol>

1) *：表示出现任意次数，0次或者n次
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "zypabcabc2021"; 
</li>
<li class="alt">
 String regStr = "zyp(abc)*"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/ea687d7ff29c3139e3a875022d1849a7.jpg" width="auto">

结果展示

2）+：表示出现至少1次或者n次，如（abc)+表示abc出现1次或者多次
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "zypabc2021"; 
</li>
<li class="alt">
 String regStr = "zyp(abc)+"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/ea057d172ebd3d772136d21c188c4827.jpg" width="auto">

结果展示

3）？：表示出现至少0次或者1次，如abc？表示c出现0次或者1次
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "zyp2021"; 
</li>
<li class="alt">
 String regStr = "zyp(abc)?"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/8ad4f01c922385306196f8943682ad31.jpg" width="auto">

结果展示

4）{n}:表示出现n次，如{2},表示匹配2次数字
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "zyp2021"; 
</li>
<li class="alt">
 String regStr = "{2}"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/553d6b57147ae4a6d7e625ab6527bd5f.jpg" width="auto">

结果展示

5）{n,}表示至少出现n次，如{3,}表示匹配至少3次数字
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "zyp2021"; 
</li>
<li class="alt">
 String regStr = "{2,}"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0));
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/40374ebc554611a6ce90b13081640d6e.jpg" width="auto">

结果展示

6）{n,m}表示出现至少n次，最多m次，如{2,4}表示匹配次数2-4次数字
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "zyp2021"; 
</li>
<li class="alt">
 String regStr = "{2,4}"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/cba772dc95dc14f104c0a06a2ef052f5.jpg" width="auto">

结果展示
<h3>
定位符 </h3>
<ol class="dp-xml">
<li class="alt">
/** 
</li>
<li class="alt">
 * 定位符 
</li>
<li class="alt">
 * ^:表示字符串以什么开头的意思。如：有一个字符串123abc，正则为^+*(必须已数字开头),则能成功匹配上。如果字符串为a123abc则匹配不上 
</li>
<li class="alt">
 * $:表示字符串以什么结束的意思。如：有一个字符串123abc，正则为^++$(表示以数字开头，字母结尾)则能成功匹配上。如果字符串为a123abc1则匹配不上 
</li>
<li class="alt">
 * \\b:表示边缘匹配(字符串的结尾或者空格之后)。有一个字符串abc123abc，正则为abc\\b,匹配到的为最后的那个abc 
</li>
<li class="alt">
 * \\B:与\\b相反 
</li>
<li class="alt">
 */ 
</li>
</ol>

1) ^:表示字符串以什么开头的意思
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "2021zyp"; 
</li>
<li class="alt">
 String regStr = "^+"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/47ea87e6ef13a066403a4a7391ab1802.jpg" width="auto">

结果展示

2) $:表示字符串以什么结束的意思
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "2021zyp"; 
</li>
<li class="alt">
 String regStr = "$"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li>
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/2a500aeceb9a08da2e136b0b28834600.jpg" width="auto">

没有匹配到，因为要以数字结束

3) \\b:表示边缘匹配(字符串的结尾或者空格之后)
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "zyp2021zyp"; 
</li>
<li class="alt">
 String regStr = "zyp\\b"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/69f3e33bb226421b0b253de6c5715b7e.jpg" width="auto">

匹配到的是最后一个“zyp”

4) \\B:与\\b相反
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "zyp2021zyp"; 
</li>
<li class="alt">
 String regStr = "zyp\\B"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li>
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/c3a872780113f7e7e3f0e585db3e0b9d.jpg" width="auto">

匹配到的是第一个“zyp”
<h3>
分组 </h3>
<ol class="dp-xml">
<li class="alt">
/** 
</li>
<li class="alt">
 * 分组:可分为捕获分组和非捕获分组 
</li>
<li class="alt">
 * 1.捕获分组: 
</li>
<li class="alt">
 * 1）如（\\d\\d）(\\d\\d)表示匹配4位数字，如果字符串位2021abcd， 
</li>
<li class="alt">
 * 我们通过matcher.group(0)得到2021 
</li>
<li class="alt">
 * 通过matcher.group(1)得到20 
</li>
<li class="alt">
 * 通过matcher.group(2）得到21 
</li>
<li class="alt">
 * 由此可见（）起到分组的作用 
</li>
<li class="alt">
 * 
</li>
<li class="alt">
 * 2）如（?<a1>\\d\\d）(?<a2>\\d\\d)表示匹配4位数字，如果字符串位2021abcd， 
</li>
<li class="alt">
 * 我们通过matcher.group(0)得到2021 
</li>
<li class="alt">
 * 通过matcher.group(1)得到20,还可以通过matcher.group(a1)得到20 
</li>
<li class="alt">
 * 通过matcher.group(2）得到21，还可以通过matcher.group(a2)得到21 
</li>
<li class="alt">
 * 由此可见（）起到分组的作用 
</li>
<li class="alt">
 * 
</li>
<li class="alt">
 * 2.非捕获分组：不能通过group(1)或者group(2)获取值 
</li>
<li class="alt">
 * 1）如20(?:20｜21｜22)表示匹配2020｜2021｜2022 
</li>
<li class="alt">
 * 2) 如20(?=20|21|22)表示匹配2020或2021或2022中的20 
</li>
<li class="alt">
 * 3)如20(?!20|21|22)表示匹配不匹配2020或2021或2022中的20，匹配其它20 
</li>
<li class="alt">
 * 
</li>
<li class="alt">
 */ 
</li>
</ol>
<h3>
捕获分组</h3>

1）如（\\d\\d）(\\d\\d)表示匹配4位数字，如果字符串为2021abcd，
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "2021abcd"; 
</li>
<li class="alt">
 String regStr = "(\\d\\d)(\\d\\d)"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("matcher.group(0):"+matcher.group(0)); 
</li>
<li class="alt">
 System.out.println("分组一:matcher.group(1):"+matcher.group(1)); 
</li>
<li class="alt">
 System.out.println("分组二:matcher.group(2):"+matcher.group(2)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/b3b2b0dcf25db8f5d969778e4c12ae0e.jpg" width="auto">

结果展示

结论：由此可见()会将正则分组，并按顺序给出编号，从1开始

2) (?<a1>\\d\\d）(?<a2>\\d\\d)表示匹配4位数字，如果字符串位2021abcd
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "2021abcd"; 
</li>
<li class="alt">
 String regStr = "(?<a1>\\d\\d)(?<a2>\\d\\d)"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("matcher.group(0):"+matcher.group(0)); 
</li>
<li class="alt">
 System.out.println("分组一:matcher.group(1):"+matcher.group(1)); 
</li>
<li class="alt">
 System.out.println("分组二:matcher.group(2):"+matcher.group(2)); 
</li>
<li class="alt">
 System.out.println("分组名a1:matcher.group(1):"+matcher.group("a1")); 
</li>
<li class="alt">
 System.out.println("分组名a2:matcher.group(2):"+matcher.group("a2")); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/a94da7f285728897cccf5bbf668839af.jpg" width="auto">

结果展示

结论：由此可见()除了能将正则分组，还能按顺序给出编号，从1开始。还可以给分组取名字，并根据名字获取对应匹配的值
<h3>
非捕获分组</h3>

1）如20(?:20｜21｜22)表示匹配2020｜2021｜2022
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "2021a2022B2023"; 
</li>
<li class="alt">
 String regStr = "20(?:20|21|22)"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为:"+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/a7720926731dc806fb57ad434402e505.jpg" width="auto">

结果展示

2）如20(?=20|21|22)表示匹配2020或2021或2022中的20
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "2021a2022B2023"; 
</li>
<li class="alt">
 String regStr = "20(?=20|21|22)"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为:"+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li class="alt">
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/c285a416b48238d5067d515605bf8afb.jpg" width="auto">

这里匹配到的20，为2021和2022中的20

3）如20(?!20|21|22)表示匹配不匹配2020或2021或2022中的20，匹配其它20
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
public void test2(){ 
</li>
<li class="alt">
 String str = "2021a2022B2023"; 
</li>
<li class="alt">
 String regStr = "20(?!20|21|22)"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为:"+matcher.group(0)); 
</li>
<li class="alt">
 } 
</li>
<li>
} 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/c06839f8e9b2b0ac4e40612851f87761.jpg" width="auto">

这里匹配到的20为2023中的20
<h3>
反向引用 </h3>
<ol class="dp-xml">
<li class="alt">
/** 
</li>
<li class="alt">
 * 反向引用 
</li>
<li class="alt">
 * 如果我们要找到一个字符串中连续4位威数字，并且第一位和第4位要相同，第二位和第三位相同。 
</li>
<li class="alt">
 * 这时候我们使用反向引用就很简单 
</li>
<li class="alt">
 * 反向引用的内部用法:\\n其中n代表分组号，如：字符串12345678870008，正则为(\\d)(\\d)\\2\\1 
</li>
<li class="alt">
 * 反向引用的外部用法:$n其中n代表分组号 
</li>
<li class="alt">
 */ 
</li>
</ol>

字符串12345678870008，正则为(\\d)(\\d)\\2\\1
<ol class="dp-xml">
<li class="alt">
@Test 
</li>
<li class="alt">
 public void test2(){ 
</li>
<li class="alt">
 String str = "12345678870008"; 
</li>
<li class="alt">
 /** 
</li>
<li class="alt">
 * 第一个（\\d）会分配的组为1 
</li>
<li class="alt">
 * 第2个（\\d）会分配的组为2 
</li>
<li class="alt">
 * \\2:表示引用组2的值，因此2和3的值就会相同 
</li>
<li class="alt">
 * \\1:表示引用组1的值，因此1和4的值会相同 
</li>
<li class="alt">
 */ 
</li>
<li class="alt">
 String regStr = "(\\d)(\\d)\\2\\1"; 
</li>
<li class="alt">
 Pattern compile = Pattern.compile(regStr); 
</li>
<li class="alt">
 Matcher matcher = compile.matcher(str); 
</li>
<li class="alt">
 while(matcher.find()){ 
</li>
<li class="alt">
 System.out.println("匹配到的数据为："+matcher.group(0)); 
</li>
<li>
 } 
</li>
<li class="alt">
 } 
</li>
</ol>

<img title="Linux Shell 正则表达式" alt="Linux Shell 正则表达式" border="0" height="auto" src="https://zhuji.jb51.net/uploads/img/202305/afd8f767c1820fa26eb3d5be2b33f1aa.jpg" width="auto">

结果展示

原文链接：https://mp.weixin.qq.com/s/uJD7O_XsopwwMXdpPZJ0SA

頁: [1]

琼殿技术论坛's Archiver

Linux Shell 正则表达式