1、 读写文件
#!/usr/bin/env python
# -*- coding:utf-8 -*-
# @Time : 2018/1/25 20:49
# @Author : zhouyuyao
# @File : demonWrite.py
# PyCharm 2017.3.2 (Community Edition)
# Build #PC-173.4127.16, built on December 19, 2017
# JRE: 1.8.0_152-release-1024-b8 amd64
# JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
# Windows 10 10.0
# Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 18:41:36)
# [MSC v.1900 64 bit (AMD64)] on win32
if __name__== "__main__":
filename = input("Please input the name of file:")
f = open(filename,"w") # 以写的形式打开一个文件
while 1: # 1 的效率是最高的
context = input("Please input context('EOF' will close file): ")
if context == "EOF":
f.close()
break
else:
f.write(context)
f.write("\n")
fRead = open(filename)
readContext = fRead.read()
print("------------start-------------")
print(readContext)
print("-------------end--------------")
fRead.close()
运行结果:
Please input the name of file:z.log
Please input context('EOF' will close file): hello
Please input context('EOF' will close file): the weather is cool
Please input context('EOF' will close file): you have wear more clothes
Please input context('EOF' will close file): EOF
------------start-------------
hello
the weather is cool
you have wear more clothes
-------------end--------------
2、 读取文件方法
import codecs
ENCODING = "utf-8" # 字符集
f = open("z.log",encoding=ENCODING)
print(f.name) # 文件名
print(f.readline()) # 读取成列表的形式
print(f.readlines()) # 读取成列表的形式
with codecs.open("z.log","r",encoding=ENCODING) as f:
print(f.read())
3、 编码问题
编码:
支持中文的编码:utf-8,gbk,gb2312
decode 解码
encode 编码
在Python2中不定义代码的编码排头,在内容中出现中文时会报错。
Python默认将代码文件内容当做ASCII编码处理,但是ASCII编码不存在中文,因为则会抛出异常。
解决问题之道就是要让Python之道文件中使用的是什么编码形式,对于中文,可以用的常见编码有utf-8,gbk和gb2312等,只需在代码文件的最前端添加如下内容即可:
# -*- coding:utf-8 -*-
Python转码的过程:
原有编码 ——> Unicode编码 ——> 目的编码
python会自动将带中文的字符串解码成Unicode,然后再编码成gbk,因为解码是字典进行的,如果没有指明解码方式,就会使用sys,defaultencoding指明的方式来解码。
方法一:s.decode("utf-8").encoding("gbk")
4、对文件进行排序
#!/usr/bin/env python
# -*- coding:utf-8 -*-
# @Time : 2018/1/25 23:06
# @Author : zhouyuyao
# @File : sortUIDPasswd.py
# PyCharm 2017.3.2 (Community Edition)
# Build #PC-173.4127.16, built on December 19, 2017
# JRE: 1.8.0_152-release-1024-b8 amd64
# JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
# Windows 10 10.0
# Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 18:41:36)
# [MSC v.1900 64 bit (AMD64)] on win32
import codecs
file = "passwd"
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"))
python3的新特性对文本和二进制数据作了更为清晰的区分,
文本总是Unicode,由str类型表示,
二进制则是由bytes类型表示
字符串可以encode编码成字节包,而字节包可以decode解码成字符串