Python中的内存影射文件
2019-03-27 本文已影响0人
louyang
1. 新建一个文本文件
#!/usr/bin/python3
import mmap
with open("hello.txt", "w") as f:
f.write("Hello Python\n")
f.write("Hello programming\n")
$ ./a.py && cat hello.txt
Hello Python
Hello programming
2. 打开一个内存影射文件，并操作
#!/usr/bin/python3
import mmap
with open("hello.txt", "w") as f:
f.write("Hello Python\n")
f.write("Hello programming\n")
with open("hello.txt", "r+") as f:
map = mmap.mmap(f.fileno(), 0)
print(map[:])
$ ./a.py
b'Hello Python\nHello programming\n'
3. 修改内存，就是修改文件
#!/usr/bin/python3
import mmap
with open("hello.txt", "w") as f:
f.write("Hello Python\n")
f.write("Hello programming\n")
with open("hello.txt", "r+") as f:
map = mmap.mmap(f.fileno(), 0)
print(map[:])
map[6:12] = b'World!'
print(map.readline())
map.close()
$ ./e.py && cat hello.txt
b'Hello Python\nHello programming\n'
b'Hello World!\n'
Hello World!
Hello programming
