class StudentInfoManager:
    def __init__(self):
        self.students = []
 
    def add_student(self, student_id, name, age, gender):
        """添加学生信息"""
        student = {
            'student_id': student_id,
            'name': name,
            'age': age,
            'gender': gender
        }
        self.students.append(student)
        print(f"学生 {name} 添加成功！")
 
    def display_students(self):
        """显示所有学生信息"""
        if not self.students:
            print("当前没有学生信息。")
            return
        print("所有学生信息：")
        for index, student in enumerate(self.students, start=1):
            print(f"{index}. 学生ID: {student['student_id']}, 姓名: {student['name']}, 年龄: {student['age']}, 性别: {student['gender']}")
 
    def find_student_by_id(self, student_id):
        """通过学号查询学生信息"""
        for student in self.students:
            if student['student_id'] == student_id:
                return student
        print("未找到对应学号的学生信息。")
        return None
 
    def find_student_by_name(self, name):
        """通过姓名查询学生信息（这里简单实现为返回第一个匹配项）"""
        for student in self.students:
            if student['name'] == name:
                return student
        print("未找到对应姓名的学生信息。")
        return None
 
    def delete_student_by_id(self, student_id):
        """通过学号删除学生信息"""
        for i, student in enumerate(self.students):
            if student['student_id'] == student_id:
                del self.students[i]
                print(f"学生ID为 {student_id} 的学生信息已删除。")
                return
        print("未找到对应学号的学生信息，无法删除。")
 
    def update_student_info(self, student_id, **kwargs):
        """修改学生信息，通过学号定位，然后更新其他字段"""
        student = self.find_student_by_id(student_id)
        if student:
            for key, value in kwargs.items():
                if key in student:
                    student[key] = value
            print(f"学生ID为 {student_id} 的信息已更新。")
        else:
            print("未找到对应学号的学生信息，无法更新。")
 
# 使用示例
manager = StudentInfoManager()
manager.add_student('001', '张三', 20, '男')
manager.add_student('002', '李四', 21, '女')
manager.display_students()
 
student = manager.find_student_by_id('001')
if student:
    print(f"找到的学生信息：{student}")
 
manager.update_student_info('001', age=21)
manager.display_students()
 
manager.delete_student_by_id('002')
manager.display_students()