第一部分day5 文件操作

#-----文件操作-----

文件操作模式 1、"r" 读 2、"w" 清空写入 3、"a" 追加 4、"r+" 读写模式，可读可写 5、"w+" 写读模式，可写可读 6、"a+" 追加模式

1 with open("小重山","r",encoding="utf-8") as f:
2     data = f.read()
3     print(data)
4     f.close()

readlines 方法

1 with open("小重山","r",encoding="utf-8") as f:
2     data = f.readlines()
3     for i in data:
4         print(i.strip())
5 
6 with open("小重山1","w",encoding="utf-8") as f:
7     f.write("昨夜寒蛩不住鸣。惊回千里梦，已三更。起来独自绕阶行。")

#在文件中第6行操作

 1 with open("小重山","r",encoding="utf-8") as f:
 2     # print(f.fileno()) #文件句柄 #3
 3     num1 = 0
 4     for i in f.readlines():
 5         num1 += 1
 6         if num1 == 6:
 7             i = ''.join([i.strip(),'ok'])
 8         print(i.strip())
 9 
10 with open("小重山","r",encoding="utf-8") as f:
11     num1 = 0
12     for i in f:  #for循环内部将f 对象做成一个迭代器，用一行取一行
13         num1 += 1
14         if num1 == 4:
15             i = "".join([i.strip(),"ok"])
16         print(i.strip())

#flush 方法（简单版进度条）

 1 import time,sys
 2 
 3 for i in range(30):
 4     sys.stdout.write("*")
 5     time.sleep(0.2)
 6     sys.stdout.flush()
 7 
 8 for i in range(30):
 9     print("*",end="",flush=true)
10     time.sleep(0.2)

#truncate 截断

1 with open("小重山1","a",encoding="utf-8") as f:
2     f.truncate(6) #昨夜

#r+ 模式 光标以起始0开始

1 with open("小重山1","a+",encoding="utf-8") as f:
2     f.write("岳飞") #写入文件最后
3     f.close()

#w+ 模式

1 with open("小重山1","w+",encoding="utf-8") as f:
2     f.write("岳飞")
3     print(f.tell()) #6
4     f.seek(0)
5     print(f.readline())

#a+ 模式 光标以末尾开始

1 with open("小重山1","a+",encoding="utf-8") as f:
2     print(f.tell())
3     f.write("岳飞")
4     print(f.tell())
5     print(f.readline())

#文件修改

 1 # f_read = open("小重山1",'r',encoding="utf-8")
 2 # f_write = open("小重山2",'w',encoding="utf-8")
 3 #with 同时管理多个文件对象
 4 with open("小重山1",'r',encoding="utf-8") as f_read,open("小重山2",'w',encoding="utf-8") as f_write:
 5     num1 = 0
 6     for line in f_read:
 7         num1 += 1
 8         if num1 == 5:
 9             line = "".join([line.strip(),"dream\n"])
10         f_write.write(line)
11         print(line.strip())
12     f_write.close()
13     f_read.close()