【python】 全角半角轉換

以輸入爲GB18030編碼字符串爲例：

#把全角字符串轉半角
def tobanjiao(string):
        ustring = string.decode('GB18030')
        rstring = ""
        for uchar in ustring:
                inside_code=ord(uchar)  
                if inside_code==0x3000:  
                        inside_code=0x0020  
                else:  
                        inside_code-=0xfee0  

                if inside_code<0x0020 or inside_code>0x7e:
                        rstring += uchar.encode('GB18030')
                else:
                        rstring += unichr(inside_code).encode('GB18030')

        return rstring;