【python】IO系列

1. 文件IO

1.1 file read

样本C:\FILE\ifconfig.txt

[email protected] test# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:50:56:A2:14:55
          inet addr:10.180.137.68  Bcast:10.180.255.255  Mask:255.255.0.0
          inet6 addr: fe80::250:56ff:fea2:1455/64 Scope:Link

file.readline([size])读取指定size bytes的整行，返回字符串

with open("C:\FILE\ifconfig.txt") as f:
    print f.name
    print repr(f.readline())

执行结果

C:\Python27\python.exe C:/PycharmProjects/p3/src/pyproject1/iotest/fileIOtest.py
C:\FILE\ifconfig.txt
‘[root@webserver1 test]# ifconfig\n‘

file.read([size])

读取指定size bytes的所有直到EOF，返回字符串

with open("C:\FILE\ifconfig.txt") as f:
    print f.name
    print repr(f.read())    

运行结果

C:\Python27\python.exe C:/PycharmProjects/p3/src/pyproject1/iotest/fileIOtest.py
C:\FILE\ifconfig.txt
‘root@webserver1 test# ifconfig\neth0      Link encap:Ethernet  HWaddr 00:50:56:A2:14:55  \n          inet addr:10.180.137.68  Bcast:10.180.255.255  Mask:255.255.0.0\n          inet6 addr: fe80::250:56ff:fea2:1455/64 Scope:Link\n ‘

Process finished with exit code 0

file.readlines([sizehint])

读取指定size bytes的所有直到EOF，返回每行构成的list

with open("C:\FILE\ifconfig.txt") as f:
    print f.name
    print repr(f.readlines())

运行结果

C:\Python27\python.exe C:/PycharmProjects/p3/src/pyproject1/iotest/fileIOtest.py
C:\FILE\ifconfig.txt
[‘root@webserver1 test# ifconfig\n‘, ‘eth0      Link encap:Ethernet  HWaddr 00:50:56:A2:14:55  \n‘, ‘          inet addr:10.180.137.68  Bcast:10.180.255.255  Mask:255.255.0.0\n‘, ‘          inet6 addr: fe80::250:56ff:fea2:1455/64 Scope:Link\n‘, ‘ ‘]

1.2 file write

Unix/Linux系统里，每行结尾只有“<换行>”，即“\n”;

Windows系统里面，每行结尾是“<回车><换行>”，即“\r\n”;

Mac系统里，每行的结尾是“"<回车>”,即“\r”

file.write(str)

f = open("C:\FILE\ifconfig2.txt", ‘w+‘)
f.write("foooo" + "\n")
f.write("barr")f.close()

C:\FILE\ifconfig2.txt

foooo
barr

file.writelines(sequence)

f = open("C:\FILE\ifconfig2.txt", ‘w+‘)
towrite = ["ffffffoooo\n","barbarbar\n","foobarfoobar"]
f.writelines(towrite)
f.close()

C:\FILE\ifconfig2.txt

ffffffoooo
barbarbar
foobarfoobar