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"Hello world"

# 将Unicode转化为普通Python字符串："encode"

utf8string = unicodestring.encode("utf-8")

asciistring = unicodestring.encode("ascii")

isostring = unicodestring.encode("ISO-8859-1")

utf16string = unicodestring.encode("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")

assert plainstring1 == plainstring2 == plainstring3 == plainstring4

str中文转unicode

unicode(text,"gbk")