分页读取文件内容

#5.随意写一个20行以上的文件(divmod)
# 运行程序，先将内容读到内存中，用列表存储。
# l = []
# 提示：一共有多少页
# 接收用户输入页码，每页5条，仅输出当页的内容
def read_page(bk_list,n,endline=None):
    startline = 5 * (n-1)
    endline = endline+startline-1 if endline else startline + 4
    # print(startline,endline)
    for i in range(startline,endline+1):
        print(bk_list[i],end = '')

def read_book(filename):
    f = open(filename)
    book_list = f.readlines()
    f.close()
    return book_list

book_list = read_book('tmp_file')
line_num = len(book_list)

x,y = divmod(line_num,5)

# if y:
#     page = x+1
# else:
#     page = x
page = x+1 if y else x
print('一共有%s页'%page)
while True:
    page_num = input('请输入您要阅读的页码 ： ').strip()
    if page_num.isdigit():
        page_num = int(page_num)
        if page_num < page:
            read_page(book_list,page_num)
        elif page_num == page:
            read_page(book_list,page_num,y)
        else:
            print('您输入的内容有误')