python decode unicode encode

       字符串在Python内部的表示是unicode编码，因此，在做编码转换时，通常需要以unicode作为中间编码，即先将其他编码的字符串解码（decode）成unicode，再从unicode编码（encode）成另一种编码。

       代码中字符串的默认编码与代码文件本身的编码一致，以下是不一致的两种:

        1. s = u'你好'

            该字符串的编码就被指定为unicode了，即python的内部编码，而与代码文件本身的编码(查看默认编码：import sys   print('hello',sys.getdefaultencoding())  ascii 。设置默认编码：import sys reload(sys)  sys.setdefaultencoding('utf-8')))无关。因此，对于这种情况做编码转换，只需要直接使用encode方法将其转换成指定编码即可.

        2. # -*- coding: utf-8 -*-

            s = ‘你好’

            此时为utf-8编码，ascii编码不能显示汉字

isinstance(s, unicode)  #用来判断是否为unicode ,是返回True，不是返回False

unicode(str,'gb2312')与str.decode('gb2312')是一样的，都是将gb2312编码的str转为unicode编码 

使用str.__class__可以查看str的编码形式

原理说了半天，最后来个包治百病的吧：）

---

#!/usr/bin/env python
#coding=utf-8
s="中文"

if isinstance(s, unicode):
#s=u"中文"
print s.encode('gb2312')
else:
#s="中文"
print s.decode('utf-8').encode('gb2312')

语音模块代码：

# -*- coding: utf-8 -*-import
import sys
print('hello',sys.getdefaultencoding())
def xfs_frame_info(words):

    #decode utf-8 to python internal unicode coding
    isinstance(words,unicode)
    wordu = words.decode('utf-8')

    #encode python unicode to gbk
    data = wordu.encode('gbk')
    
    length = len(data) + 2

    frame_info = bytearray(5)
    frame_info[0] = 0xfd
    frame_info[1] = (length >> 8)
    frame_info[2] = (length & 0x00ff)
    frame_info[3] = 0x01
    frame_info[4] = 0x01

       
    buf = frame_info + data
    print("buf:",buf)

    return buf

if __name__ == "__main__":

    print("hello world")
    words1= u'你好'
    #encodetype = isinstance(words1,unicode)
    #print("encodetype",encodetype)
    print("origin unicode", words1)
    
    words= words1.encode('utf-8')
    print("utf-8 encoded", words)
    a = xfs_frame_info(words)
    print('a',a)

if __name__ == "__main__":

    print("hello world")
    words1= '你好'
    print("oringe utf-8 encode:",words1)
    encodetype = isinstance(words1,unicode)
    wordu = words1.decode('utf-8')
    print("unicode from utf-8 decode:",wordu)
    #encodetype = isinstance(words1,utf-8)
    #encodetype = isinstance(words1,'ascii')
    #print("encodetype",encodetype)
    #print("origin unicode", words1)
    
    word_utf8 = wordu.encode('utf-8')
    #encodetype2 = isinstance(words,utf8)
    #print("encodetype2",encodetype2)
    print("utf-8 encoded",word_utf8)
    a = xfs_frame_info(word_utf8)
    print('a',a)

你好前不加u''时，要多一步decode为unicode