文件操作
对文件操作流程
- 打开文件，得到文件句柄并赋值给一个变量
- 通过句柄对文件进行操作
- 关闭文件
现有文件如下
1 Somehow, it seems the love I knew was always the most destructive kind 2 不知为何，我经历的爱情总是最具毁灭性的的那种 3 Yesterday when I was young 4 昨日当我年少轻狂 5 The taste of life was sweet 6 生命的滋味是甜的 7 As rain upon my tongue 8 就如舌尖上的雨露 9 I teased at life as if it were a foolish game 10 我戏弄生命 视其为愚蠢的游戏 11 The way the evening breeze 12 就如夜晚的微风 13 May tease the candle flame 14 逗弄蜡烛的火苗 15 The thousand dreams I dreamed 16 我曾千万次梦见 17 The splendid things I planned 18 那些我计划的绚丽蓝图 19 I always built to last on weak and shifting sand 20 但我总是将之建筑在易逝的流沙上 21 I lived by night and shunned the naked light of day 22 我夜夜笙歌 逃避白昼赤裸的阳光 23 And only now I see how the time ran away 24 事到如今我才看清岁月是如何匆匆流逝 25 Yesterday when I was young 26 昨日当我年少轻狂 27 So many lovely songs were waiting to be sung 28 有那么多甜美的曲儿等我歌唱 29 So many wild pleasures lay in store for me 30 有那么多肆意的快乐等我享受 31 And so much pain my eyes refused to see 32 还有那么多痛苦 我的双眼却视而不见 33 I ran so fast that time and youth at last ran out 34 我飞快地奔走 最终时光与青春消逝殆尽 35 I never stopped to think what life was all about 36 我从未停下脚步去思考生命的意义 37 And every conversation that I can now recall 38 如今回想起的所有对话 39 Concerned itself with me and nothing else at all 40 除了和我相关的 什么都记不得了 41 The game of love I played with arrogance and pride 42 我用自负和傲慢玩着爱情的游戏 43 And every flame I lit too quickly, quickly died 44 所有我点燃的火焰都熄灭得太快 45 The friends I made all somehow seemed to slip away 46 所有我交的朋友似乎都不知不觉地离开了 47 And only now I‘m left alone to end the play, yeah 48 只剩我一个人在台上来结束这场闹剧 49 Oh, yesterday when I was young 50 噢 昨日当我年少轻狂 51 So many, many songs were waiting to be sung 52 有那么那么多甜美的曲儿等我歌唱 53 So many wild pleasures lay in store for me 54 有那么多肆意的快乐等我享受 55 And so much pain my eyes refused to see 56 还有那么多痛苦 我的双眼却视而不见 57 There are so many songs in me that won‘t be sung 58 我有太多歌曲永远不会被唱起 59 I feel the bitter taste of tears upon my tongue 60 我尝到了舌尖泪水的苦涩滋味 61 The time has come for me to pay for yesterday 62 终于到了付出代价的时间 为了昨日 63 When I was young 64 当我年少轻狂
待处理文件内容
基本操作
1 f = open(‘lyrics‘) #打开文件 2 first_line = f.readline() 3 print(‘first line:‘,first_line) #读一行 4 print(‘我是分隔线‘.center(50,‘-‘)) 5 data = f.read()# 读取剩下的所有内容,文件大时不要用 6 print(data) #打印文件 7 8 f.close() #关闭文件
打开文件的模式有：
- r，只读模式（默认）。
- w，只写模式。【不可读；不存在则创建；存在则删除内容；】
- a，追加模式。【可读； 不存在则创建；存在则只追加内容；】
"+" 表示可以同时读写某个文件
- r+，可读写文件。【可读；可写；可追加】
- w+，写读
- a+，同a
"U"表示在读取时，可以将 \r \n \r\n自动转换成 \n （与 r 或 r+ 模式同使用）
- rU
- r+U
"b"表示处理二进制文件（如：FTP发送上传ISO镜像文件，linux可忽略，windows处理二进制文件时需标注）
- rb
- wb
- ab
其它语法
1 def close(self): # real signature unknown; restored from __doc__ 2 """ 3 Close the file. 4 5 A closed file cannot be used for further I/O operations. close() may be 6 called more than once without error. 7 """ 8 pass 9 10 def fileno(self, *args, **kwargs): # real signature unknown 11 """ Return the underlying file descriptor (an integer). """ 12 pass 13 14 def isatty(self, *args, **kwargs): # real signature unknown 15 """ True if the file is connected to a TTY device. """ 16 pass 17 18 def read(self, size=-1): # known case of _io.FileIO.read 19 """ 20 注意，不一定能全读回来 21 Read at most size bytes, returned as bytes. 22 23 Only makes one system call, so less data may be returned than requested. 24 In non-blocking mode, returns None if no data is available. 25 Return an empty bytes object at EOF. 26 """ 27 return "" 28 29 def readable(self, *args, **kwargs): # real signature unknown 30 """ True if file was opened in a read mode. """ 31 pass 32 33 def readall(self, *args, **kwargs): # real signature unknown 34 """ 35 Read all data from the file, returned as bytes. 36 37 In non-blocking mode, returns as much as is immediately available, 38 or None if no data is available. Return an empty bytes object at EOF. 39 """ 40 pass 41 42 def readinto(self): # real signature unknown; restored from __doc__ 43 """ Same as RawIOBase.readinto(). """ 44 pass #不要用,没人知道它是干嘛用的 45 46 def seek(self, *args, **kwargs): # real signature unknown 47 """ 48 Move to new file position and return the file position. 49 50 Argument offset is a byte count. Optional argument whence defaults to 51 SEEK_SET or 0 (offset from start of file, offset should be >= 0); other values 52 are SEEK_CUR or 1 (move relative to current position, positive or negative), 53 and SEEK_END or 2 (move relative to end of file, usually negative, although 54 many platforms allow seeking beyond the end of a file). 55 56 Note that not all file objects are seekable. 57 """ 58 pass 59 60 def seekable(self, *args, **kwargs): # real signature unknown 61 """ True if file supports random-access. """ 62 pass 63 64 def tell(self, *args, **kwargs): # real signature unknown 65 """ 66 Current file position. 67 68 Can raise OSError for non seekable files. 69 """ 70 pass 71 72 def truncate(self, *args, **kwargs): # real signature unknown 73 """ 74 Truncate the file to at most size bytes and return the truncated size. 75 76 Size defaults to the current file position, as returned by tell(). 77 The current file position is changed to the value of size. 78 """ 79 pass 80 81 def writable(self, *args, **kwargs): # real signature unknown 82 """ True if file was opened in a write mode. """ 83 pass 84 85 def write(self, *args, **kwargs): # real signature unknown 86 """ 87 Write bytes b to file, return number written. 88 89 Only makes one system call, so not all of the data may be written. 90 The number of bytes actually written is returned. In non-blocking mode, 91 returns None if the write would block. 92 """ 93 pass
with语句
为了避免打开文件后忘记关闭，可以通过管理上下文，即：
1 with open(‘log‘,‘r‘) as f: 2 3 ...
如此方式，当with代码块执行完毕时，内部会自动关闭并释放文件资源。
在Python 2.7 后，with又支持同时对多个文件的上下文进行管理，即：
1 with open(‘log1‘) as obj1, open(‘log2‘) as obj2: 2 pass
程序练习
程序1: 实现简单的shell sed替换功能
程序2:修改haproxy配置文件
需求：
1 1、查
2 输入：www.oldboy.org
3 获取当前backend下的所有记录
4
5 2、新建
6 输入：
7 arg = {
8 ‘bakend‘: ‘www.oldboy.org‘,
9 ‘record‘:{
10 ‘server‘: ‘100.1.7.9‘,
11 ‘weight‘: 20,
12 ‘maxconn‘: 30
13 }
14 }
15
16 3、删除
17 输入：
18 arg = {
19 ‘bakend‘: ‘www.oldboy.org‘,
20 ‘record‘:{
21 ‘server‘: ‘100.1.7.9‘,
22 ‘weight‘: 20,
23 ‘maxconn‘: 30
24 }
25 }
需求
1 global 2 log 127.0.0.1 local2 3 daemon 4 maxconn 256 5 log 127.0.0.1 local2 info 6 defaults 7 log global 8 mode http 9 timeout connect 5000ms 10 timeout client 50000ms 11 timeout server 50000ms 12 option dontlognull 13 14 listen stats :8888 15 stats enable 16 stats uri /admin 17 stats auth admin:1234 18 19 frontend oldboy.org 20 bind 0.0.0.0:80 21 option httplog 22 option httpclose 23 option forwardfor 24 log global 25 acl www hdr_reg(host) -i www.oldboy.org 26 use_backend www.oldboy.org if www 27 28 backend www.oldboy.org 29 server 100.1.7.9 100.1.7.9 weight 20 maxconn 3000
原配置文件
字符编码与转码
详细文章:
http://www.cnblogs.com/yuanchenqi/articles/5956943.html
http://www.diveintopython3.net/strings.html
原文地址：https://www.cnblogs.com/zhq-home/p/12221862.html
时间： 2024-08-29 13:12:12