普通字符串可以用多种方式编码成Unicode字符串，具体要看你究竟选择了哪种编码：unicodestring=u"Helloworld"#将Unicode转化为普通Python字符串："encode"utf8string=de("utf-8"
)asciistring=de("ascii"
)isostring=de("ISO-8859-1"
)utf16string=de("utf-16")#将普通Python字符串转化为Unicode："decode"plainstring1=unicode(utf8string，"utf-8"
)plainstring2=unicode(asciistring，"ascii"
)plainstring3=unicode(isostring，"ISO-8859-1"
)plainstring4=unicode(utf16string，"utf-16"
)assertplainstring1==plainstring2==plainstring3==plainstring4
