f = open("D:\python学习2021\读入类型测试.txt","r",encoding = 'utf-8')
>>> a = f.read()
>>> a
'{a:11,b:22,c:33,d:44,e:55}n[1,2,3,4,5,6,7]n["列表","w","e","r","t"]n{"这","是","集","合"}n"字 符 串 类 型"'
>>> f.seek(0)
0
>>> b = f.readline()
>>> b
'{a:11,b:22,c:33,d:44,e:55}n'
>>> b = f.readline()
>>> b
'[1,2,3,4,5,6,7]n'
>>> f.seek(0)
0
>>> b = f.readlines()
>>> b
['{a:11,b:22,c:33,d:44,e:55}n', '[1,2,3,4,5,6,7]n', '["列表","w","e","r","t"]n', '{"这","是","集","合"}n', '"字 符 串 类 型"']
文件读取：
.read() 读取整个文件内容，返回字符串或字节流
.readline()读取一行， 返回字符串或者字节流
.readlines() 返回列表，但是列表里的元素（每一行）都是字符串
总结：无论哪种方法读取文件，文件的每一行都是以字符串或者字节流的方式存储的。
无论文件中的格式看似什么类型，只要文件的每一行的内容读入，那么必定是以字符串类型表示，并且行尾带有n换行符
.write(s)
.writelines(lines)
.seek(offset) 0,1,2
