python--基础4 （文件操作）

Posted 2022-01-12 du-z

python文件操作步骤

#第一步：调用文件
f=open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'r', encoding='gbk')
#第二部：使用文件
print(f.readlines())
#第三部：关闭文件
f.close()

#python中内置函数with可以自动关闭文件：
with open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'r', encoding='utf-8')as f:
    print(f.readlines())

三种调用文件的路径的写法

open(r'D:\\untitled\\venv\\Include\\blacklist.txt')  #r --read  只读，代表' '内的字符串没有其他含义不进行转义
open('D:\\\\untitled\\\\venv\\\\Include\\\\blacklist.txt')
open('D:/untitled/venv/Include/blacklist.txt')

读(rt)

read读取全部内容

with open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'r', encoding='gbk')as f:
    print(f.read())

...运行结果

艾妮
你好
hello
world

readline按行读取

with open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'r', encoding='gbk')as f:
    print(f.readline(2))

...运行结果

艾妮

readlines把内容以列表形式展现

with open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'r', encoding='gbk')as f:
    print(f.readlines())

...运行结果

['艾妮\\n', '你好\\n', 'hello\\n', 'world\\n']

覆盖写（wt）

with open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'w', encoding='utf-8')as f:
    f.write('你好不好')
with open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'r', encoding='utf-8')as f:
    print(f.readlines())

...运行结果

['你好不好']

追加写appand（at）

with open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'a', encoding='utf-8')as f:
    f.write('艾妮'+'\\n')
with open(r'D:\\untitled\\venv\\Include\\blacklist.txt', 'r', encoding='utf-8')as f:
    print(f.read())

...运行结果

你好不好
艾妮
艾妮
艾妮