读文件：
f = open("1.txt")
text = f.readlines()
print(text)写文件：
f = open("2.txt",'w')encoding='utf-8'
f.write("Hello World!")
f.close()代码:
class File():
ENCODING = "utf-8"
def wirteFile(self):
filename = input("Please input the file name: ")
f = codecs.open(filename,'w',encoding=File.ENCODING)
while 1:
context = input("Please input the file context: ")
if context == "EOF":
break
f.write(context)
f.write("\n")
def readFile(self):
print("####################STAT######################")
readfile = input("Please input your read file name: ")
fileread = codecs.open(readfile,encoding=File.ENCODING)
readContext = fileread.read()
print(readContext)
print("################### END ######################")
fileread.close()
if __name__ == '__main__':
import codecs
File = File()
File.wirteFile()
File.readFile()执行过程:
Please input the file name: fxq.log Please input the file context: Hello world! Please input the file context: My name is Fengxiaoqing Please input the file context: I'm 30 Please input the file context: I'm a bright boy.l Please input the file context: Think you very much! Please input the file context: EOF ####################STAT###################### Please input your read file name: fxq.log Hello world! My name is Fengxiaoqing I'm 30 I'm a bright boy.l Think you very much! ################### END ###################### 进程已结束,退出代码0
2. 文件方法
文件常用方法：
readline()
readlines()
next()
read()
write() 写入的是字符串
writelines() 参数是序列，比如列表，它会迭代帮你 写入文件
文件属性：
f.name
f.closed
f.encoding
f.mode
with用法：
with codec.open("1.log",encoding= "utf-8") as f:
print(f.read())3.python2的乱码问题
python2中：
import sys
reload(sys)
print(sys.getdefaultencoding())
4.python对passwd文件进行排序
密码文件：
[root@localhost ~]# cat passwd.txt root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt mail:x:8:12:mail:/var/spool/mail:/sbin/nologin operator:x:11:0:operator:/root:/sbin/nologin games:x:12:100:games:/usr/games:/sbin/nologin ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin nobody:x:99:99:Nobody:/:/sbin/nologin systemd-bus-proxy:x:999:997:systemd Bus Proxy:/:/sbin/nologin systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:998:996:User for polkitd:/:/sbin/nologin libstoragemgmt:x:997:995:daemon account for libstoragemgmt:/var/run/lsm:/sbin/nologin rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin ntp:x:38:38::/etc/ntp:/sbin/nologin abrt:x:173:173::/etc/abrt:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin chrony:x:996:994::/var/lib/chrony:/sbin/nologin tcpdump:x:72:72::/:/sbin/nologin dockerroot:x:995:992:Docker User:/var/lib/docker:/sbin/nologin saslauth:x:994:76:Saslauthd user:/run/saslauthd:/sbin/nologin mailnull:x:47:47::/var/spool/mqueue:/sbin/nologin smmsp:x:51:51::/var/spool/mqueue:/sbin/nologin
代码：
#/usr/bin/env python
# -*- coding:utf-8 -*-
# @time :2018/1/25 22:11
# @Author :FengXiaoqing
# @file :uidSort-Passwd.py
import codecs
file = "passwd.txt"
sortfile = "sortpasswd.txt"
fileContext = []
sortuid = []
with codecs.open(sortfile,'wb') as fsort:
with codecs.open(file,encoding='utf-8') as f:
fileContext += f.readlines()
for line in fileContext:
sortuid.append(int(line.split(':')[2]))
sortuid.sort()
for uid in sortuid:
for line in fileContext:
if str(uid) == line.split(":")[2]:
print(line)
fsort.write(line.encode("utf-8"))原文：http://blog.51cto.com/fengyunshan911/2065251