正则表达式-如何从字符串ABC_ABC12345_ABC_ABC.txt中仅保留ABC12345，有时它可以是ABC12345_ABC.txt

Question

正则表达式-如何从字符串ABC_ABC12345_ABC_ABC.txt中仅保留ABC12345，有时它可以是ABC12345_ABC.txt

Answer 1

您可以RegEx搜索模式^.*_(\w+\d+)_.*$以返回所需的匹配项。此模式假定所需的匹配项包含在下划线中，具有一对多字符的字母数字前缀，并以一对多数字结束。

更新：修改了模式，允许匹配可以在字符串的开头，而不是在前面加上下划线：^(.*_|)(\w+\d+)_.*$。在此模式中，您可能希望捕获第二个匹配。

Answer 2

在不太了解匹配条件的情况下(例如，它只是数字、通过下划线的任何分隔符或其他？)，我会说这可能会起作用：

string test = "ABC_ABC12345_ABC_ABC.txt";

Regex rx = new Regex(@"ABC\d+");
Match m = rx.Match(test);

if (m.Success)
    test = m.Groups[0].Value;

如果您不需要它来替换原始字符串(您只需要结果)，只需将其放入一个单独的变量。

Answer 3

using System;
using System.Text.RegularExpressions;

public class Program
{   
    public static void Main()
    {
        string string1 = "ABC_ABC12345_ABC_ABC.txt";

        Regex s1 = new Regex(@"\w{3}\d{5}");
        //if just for capital letter and only three characters and five numbers use: Regex s2 = new Regex(@"[A-Z]{3}\d{5}");
        //if the number of characters "capital letter" and numbers does not matter use: Regex s2 = new Regex(@"[A-Z]+\d+");
        //if the number of characters "capital and small letter" and numbers does not matter use: Regex s2 = new Regex(@"[A-Za-z]+\d+"); 


        Regex s2 = new Regex(@"\w{3}\d{5}\w{8}\.\w{3}");
        //if just for capital letter and only three characters and five numbers use: Regex s2 = new Regex(@"[A-Z]{3}\d{5}_[A-Z]{3}_[A-Z]{3}\.\w{3}");
        //if the number of characters "capital letter" and numbers does not matter use: Regex s2 = new Regex(@"[A-Z]+\d+_[A-Z]+_[A-Z]+\.\w{3}");
        //if the number of characters "capital and small letter" and numbers does not matter use: Regex s2 = new Regex(@"[A-Za-z]+\d+_[A-Za-z]+_[A-Za-z]+\.\w{3}");


        Match m1 = s1.Match(string1);
        Match m2 = s2.Match(string1);


        if (m1.Success){
            String result = m1.ToString();
            Console.WriteLine(result);  
        }
        else if(m2.Success){
            String result = m2.ToString();
            Console.WriteLine(result);
        }
        else{
           Console.WriteLine("No match");
        }
    }
}

测试结束后

​

​

我已经注释了第一个条件，以验证第二个条件

​

​