python 实现 全角字符 传转换成 半角字符串

Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)] on win32
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>>> def strQ2B(ustring):
#把全角字符串转半角
        ustring=ustring.decode("cp936")
        rstring=""
        for uchar in ustring:
                inside_code=ord(uchar)
                print inside_code
                if inside_code==0x3000:
                        inside_code=0x0020
                else:
                        inside_code-=0xfee0
                if inside_code<0x0020 or inside_code>0x7e:
                        rstring+=uchar.encode('cp936')
                else:
                        rstring+=(unichr(inside_code)).encode('cp936')

        return rstring

>>> strQ2B("hao　　哈　还好")