如何调用动态命名的文件？

filename = "dynamic_file.txt"
with open(filename, "r") as file:
    # 执行文件操作

var dynamicPart = "123";
var filename = "file_" + dynamicPart + ".txt";
// 执行文件操作

import java.io.File;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class DynamicFileExample {
    public static void main(String[] args) {
        String regex = "file_(\\d+).txt";
        File folder = new File("path/to/files");
        File[] files = folder.listFiles();
        
        Pattern pattern = Pattern.compile(regex);
        for (File file : files) {
            Matcher matcher = pattern.matcher(file.getName());
            if (matcher.matches()) {
                // 执行文件操作
            }
        }
    }
}