day12_文件操作的其他方法

#一、读相关

#1、readline:一次读一行
# with open(r'g.txt',mode='rt',encoding='utf-8') as f:
#     # res1=f.readline()
#     # res2=f.readline()
#     # print(res2)
#
#     while True:  #一次读一行
#         line=f.readline()
#         if len(line) == 0:
#             break
#         print(line,end='')


#2、readlines:
# with open(r'g.txt',mode='rt',encoding='utf-8') as f:
#     res=f.readlines()
#     print(res)


#强调：
#f.read 与f.readlines()都是讲内容一次性读入内存，如果内容过多过大
#会导致内存占用过大


#二、写相关
#f.writelines():
# with open(r'h.txt',mode='wt',encoding='utf-8') as f:
#     # f.write('111\n222\n333\n')
#
#     l=['1111\n','2222\n','3333\n']
#     # for line in l:
#     #     f.write(line)
#
#     f.writelines(l) #相当于上面那个for循环

# with open(r'h.txt',mode='wb') as f:

    # l=[
    #     '1111\n'.encode('utf-8'),
    #    '2222\n'.encode('utf-8'),
    #     '3333\n.'.encode('utf-8')
    # ]

    #补充一：写进去的内容时纯英文字符不用加【.encode('utf-8')】,直接在前面加上  b  也能得到bytes类型
    # l=[
    #     b'1111\n',
    #     b'2222\n',
    #     b'3333\n.'
    # ]

    #补充二：'上'.encde('utf-8')等同于bytes('上’，encoding='utf-8')
    # l=[
    #     bytes('上啊',encoding='utf-8'),
    #     bytes('冲啊',encoding='utf-8'),
    #     bytes('荣望啊',encoding='utf-8'),
    # ]
    # f.writelines(l)
'''
>>> '上'.encode('utf-8')
b'\xe4\xb8\x8a'
>>> bytes('上',encoding='utf-8')
b'\xe4\xb8\x8a'
'''

#3、flush:将内存的数据立即写进硬盘
# with open(r'h.txt',mode='wt',encoding='utf-8') as f:
#     f.write('哈哈哈')
#     f.flush()

#了解：