如何将两个带数字的文件合并到一个新文件中并对其进行排序？

def merge_and_sort_files(file1, file2, new_file):
    # 读取文件1的数字
    numbers1 = []
    with open(file1, 'r') as f1:
        for line in f1:
            number = line.strip()
            if number.isdigit():
                numbers1.append(int(number))

    # 读取文件2的数字
    numbers2 = []
    with open(file2, 'r') as f2:
        for line in f2:
            number = line.strip()
            if number.isdigit():
                numbers2.append(int(number))

    # 合并两个列表
    merged_numbers = numbers1 + numbers2

    # 对合并后的列表进行排序（升序）
    sorted_numbers = sorted(merged_numbers)

    # 写入新文件
    with open(new_file, 'w') as nf:
        for number in sorted_numbers:
            nf.write(str(number) + '\n')

# 调用函数进行文件合并和排序
merge_and_sort_files('file1.txt', 'file2.txt', 'new_file.txt')