如何在python中一次从一个大字符串中读取n个字节？

import io

def read_n_bytes_from_string(s, n):
    byte_stream = io.BytesIO(s.encode('utf-8'))  # 将字符串转换为二进制流
    data = byte_stream.read(n)  # 读取n个字节
    return data

# 示例用法
large_string = "This is a large string."
n = 5
result = read_n_bytes_from_string(large_string, n)
print(result)