10-文件管理

f = open(‘a.txt‘, encoding=‘utf-8‘)
data = f.read()
print(data)
print(‘data2------------->‘)
data2 = f.read()
print(data2)
运行结果:
hello,world.
what is your name?
how are you?
data2------------->

import os
read_f = open(‘a.txt‘, ‘r‘, encoding=‘utf-8‘)
write_f = open(‘b.txt‘, ‘w‘, encoding=‘utf-8‘)
for line in read_f.readlines():
    if line.startwith(‘4444444444‘):
        line = ‘dddddddddddd\n‘
    write_f.write(line)
read_f.close()
write_f.close()
os.remove(‘a.txt‘)
os.rename(‘b.txt‘, ‘a.txt‘)

with open(‘a.txt‘, ‘rb‘) as f:
    print(f.read())
运行结果:
b‘\xe4\xbd\xa0\xe6\x98\xaf\xe8\xb0\x81‘
with open(‘a.txt‘, ‘rb‘) as f:
    print(f.read().decode(‘utf-8‘))
运行结果:
你好

with open(‘c.txt‘, ‘wb‘) as f:
    f.write(‘你好吗‘.encode(‘utf-8‘))

with open(‘c.txt‘, ‘r+‘, encoding=‘utf-8‘) as f:
    f.truncate(3)
运行结果：
查看c.txt文件内容
你

import time
with open(‘access.log‘, ‘r‘, encoding=‘utf-8‘) as f:
    f.seek(0, 2)
    while True:
        line = f.readline().strip()
        if line:
            print(‘新增：‘, line)
        time.sleep(1)