1.str >>>list
str1 = "12345"
list1 = list(str1)
2.list >>>str
str4 = "".join(list3)
str4 = "".join(list3)
print str4
str5 = ".".join(list3)
print str5
str6 = " ".join(list3)
print str6
wwwgooglecom
www.google.com
www google com
https://blog.csdn.net/roytao2/article/details/53433373