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今天就跟大家聊聊有關(guān)C#中怎么利用正則表達(dá)式定位字符,可能很多人都不太了解,為了讓大家更加了解,小編給大家總結(jié)了以下內(nèi)容,希望大家根據(jù)這篇文章可以有所收獲。
“定位字符”所代表的是一個(gè)虛的字符,它代表一個(gè)位置,你也可以直觀地認(rèn)為“定位字符”所代表的是某個(gè)字符與字符間的那個(gè)微小間隙。
^ 表示其后的字符必須位于字符串的開始處
$ 表示其前面的字符必須位于字符串的結(jié)束處
\b 匹配一個(gè)單詞的邊界
\B 匹配一個(gè)非單詞的邊界
另外,還包括:\A 前面的字符必須位于字符處的開始處,\z 前面的字符必須位于字符串的結(jié)束處,\Z 前面的字符必須位于字符串的結(jié)束處,或者位于換行符前
下面提供一些簡(jiǎn)單的C#正則表達(dá)式之定位字符示例:
string i = "Live for nothing,die for something"; Regex r1 = new Regex("^Live for nothing,die for something$"); //r1.IsMatch(i) true Regex r2 = new Regex("^Live for nothing,die for some$"); //r2.IsMatch(i) false Regex r3 = new Regex("^Live for nothing,die for some"); //r3.IsMatch(i) true string i = @"Live for nothing, die for something";//多行 Regex r1 = new Regex("^Live for nothing,die for something$"); Console.WriteLine("r1 match count:" + r1.Matches(i).Count);//0 Regex r2 = new Regex("^Live for nothing,die for something$", RegexOptions.Multiline); Console.WriteLine("r2 match count:" + r2.Matches(i).Count);//0 Regex r3 = new Regex("^Live for nothing,\r\ndie for something$"); Console.WriteLine("r3 match count:" + r3.Matches(i).Count);//1 Regex r4 = new Regex("^Live for nothing,$"); Console.WriteLine("r4 match count:" + r4.Matches(i).Count);//0 Regex r5 = new Regex("^Live for nothing,$", RegexOptions.Multiline); Console.WriteLine("r5 match count:" + r5.Matches(i).Count);//0 Regex r6 = new Regex("^Live for nothing,\r\n$"); Console.WriteLine("r6 match count:" + r6.Matches(i).Count);//0 Regex r7 = new Regex("^Live for nothing,\r\n$", RegexOptions.Multiline); Console.WriteLine("r7 match count:" + r7.Matches(i).Count);//0 Regex r8 = new Regex("^Live for nothing,\r$"); Console.WriteLine("r8 match count:" + r8.Matches(i).Count);//0 Regex r9 = new Regex("^Live for nothing,\r$", RegexOptions.Multiline); Console.WriteLine("r9 match count:" + r9.Matches(i).Count);//1 Regex r10 = new Regex("^die for something$"); Console.WriteLine("r10 match count:" + r10.Matches(i).Count);//0 Regex r11 = new Regex("^die for something$", RegexOptions.Multiline); Console.WriteLine("r11 match count:" + r11.Matches(i).Count);//1 Regex r12 = new Regex("^"); Console.WriteLine("r12 match count:" + r12.Matches(i).Count);//1 Regex r13 = new Regex("$"); Console.WriteLine("r13 match count:" + r13.Matches(i).Count);//1 Regex r14 = new Regex("^", RegexOptions.Multiline); Console.WriteLine("r14 match count:" + r14.Matches(i).Count);//2 Regex r15 = new Regex("$", RegexOptions.Multiline); Console.WriteLine("r15 match count:" + r15.Matches(i).Count);//2 Regex r16 = new Regex("^Live for nothing,\r$\n^die for something$", RegexOptions.Multiline); Console.WriteLine("r16 match count:" + r16.Matches(i).Count);//1 //對(duì)于一個(gè)多行字符串,在設(shè)置了Multiline選項(xiàng)之后,^和$將出現(xiàn)多次匹配。 string i = "Live for nothing,die for something"; string m = "Live for nothing,die for some thing"; Regex r1 = new Regex(@"\bthing\b"); Console.WriteLine("r1 match count:" + r1.Matches(i).Count);//0 Regex r2 = new Regex(@"thing\b"); Console.WriteLine("r2 match count:" + r2.Matches(i).Count);//2 Regex r3 = new Regex(@"\bthing\b"); Console.WriteLine("r3 match count:" + r3.Matches(m).Count);//1 Regex r4 = new Regex(@"\bfor something\b"); Console.WriteLine("r4 match count:" + r4.Matches(i).Count);//1 //\b通常用于約束一個(gè)完整的單詞
看完上述內(nèi)容,你們對(duì)C#中怎么利用正則表達(dá)式定位字符有進(jìn)一步的了解嗎?如果還想了解更多知識(shí)或者相關(guān)內(nèi)容,請(qǐng)關(guān)注億速云行業(yè)資訊頻道,感謝大家的支持。
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