python（12）- 文件处理应用Ⅰ

一、读取文件，打印第三行时后面加入“徐亚平”

程序如下：

count=0
with open("test",mode="r",encoding="utf8") as f:
    for line in f:

        if count==2:
            line="".join([line.strip(),"徐亚平"])

        print(line.strip())
        count+=1

　　

 Somehow, it seems the love I knew was always the most destructive kind
 不知为何，我经历的爱情总是最具毁灭性的的那种
 Yesterday when I was young
 昨日当我年少轻狂
 The taste of life was sweet
 生命的滋味是甜的
 As rain upon my tongue
 就如舌尖上的雨露
 I teased at life as if it were a foolish game
 我戏弄生命 视其为愚蠢的游戏

test

二、修改文件，第三行时后面加入“徐亚平”

因为文件保存在相对应的内存块，故不能在文件前面和文件中间修改，只能在文件尾端追加。

故此时在第三行尾加入“徐亚平”，只能新建文件，删除原先的保留新建的满足题目要求。

程序如下：

count=0
with open("test2",encoding="utf8") as f_read,open("test3",mode="w",encoding="utf8") as f_write:
    for line in f_read:
        if count==2:
             line="".join([line.strip(),"徐亚平\n"])
        f_write.write(line)
        count+=1
import os
os.rename("test2","test2_bak")
os.rename("test3","test2")

　　

原文件test2

 Somehow, it seems the love I knew was always the most destructive kind
 不知为何，我经历的爱情总是最具毁灭性的的那种
 Yesterday when I was young
 昨日当我年少轻狂
 The taste of life was sweet
 生命的滋味是甜的
 As rain upon my tongue
 就如舌尖上的雨露
 I teased at life as if it were a foolish game
 我戏弄生命 视其为愚蠢的游戏

test2

三、打印并显示进度条

import sys
for i in range(100):
    s="\r%s%% %s"%(i+1,"#"*(i+1))
    sys.stdout.write(s)
    sys.stdout.flush()
    import time
    time.sleep(0.5)
print(s)

　　

四、修改haproxy配置文件

1、查
    输入：www.oldboy.org
    获取当前backend下的所有记录

while True:
    m = input("please input url:").strip()
    flag = False
    l = []
    with open("haproxy.conf",encoding="utf8") as f_read:          #打开文件并赋值为f_read
        for line in f_read:                                          #逐行读取文件haproxy.conf
            if line.startswith("backend") and m in line:           #如果是“backend”开头并且“m”在此行中
                flag=True                               #不打印不需要，改变标志位值，中止本次操作，重新开始for循环
                continue
             if line.startswith("backend") and flag:    #第二次读到“backend”开头所在的行，结束本层for全部循环
                break
            if flag:                                     #读到“backend”开头并且“m”后面的行，追加此行到l列表中
                l.append(line.strip())
    for i in l:                                         #逐条打印l列表中的数据
        print(i)

　　

 global
         log 127.0.0.1 local2
         daemon
         maxconn 256
         log 127.0.0.1 local2 info

 defaults
         log global
         mode http
         timeout connect 5000ms
         timeout client 50000ms
         timeout server 50000ms
         option  dontlognull

 listen  stats :8888
         stats enable
         stats uri       /admin
         stats auth      admin:1234

 frontend oldboy.org
          bind 0.0.0.0:80
          option httplog
          option httpclose
          option  forwardfor
          log global
          acl www hdr_reg(host) -i www.oldboy.org
          use_backend www.oldboy.org if www

 backend www.oldboy1.org
         server 10.10.0.10 10.10.0.10 weight 9999 maxconn 33
         server 10.10.10.1 10.10.10.1 weight 22   maxconn 2000
         server 2.2.2.4 2.2.2.4       weight 20   maxconn 3000

 backend www.oldboy2.org
         server 3.3.3.3 3.3.3.3 weight 20 maxconn 3000

 backend www.oldboy20.org
         server 10.10.0.10 10.10.0.10 weight 9999 maxconn 33

 data=input():    {"backend":"www.oldboy1.org","record":{server:...,weight:...,maxconn:...}}

haproxy配置文件