python获取中文拼音首字母以进行检索

最近在项目中有这个一个需求，就是要进行首字母查询，就是搜索"王菲"，可以用"wf"来搜索。

搜索了一下，没有现在的python代码，倒有现成的php代码。修改一下，成了以下的代码：

def multi_get_letter(str_input):

if isinstance(str_input, unicode):
unicode_str = str_input
else:
try:
unicode_str = str_input.decode('utf8')
except:
try:
unicode_str = str_input.decode('gbk')
except:
print 'unknown coding'
return

return_list = []
for one_unicode in unicode_str:
print single_get_first(one_unicode)
return_list.append(single_get_first(one_unicode))
return "".join(return_list)

def single_get_first(unicode1):
str1 = unicode1.encode('gbk')
try:
ord(str1)
return str1
except:
asc = ord(str1[0]) * 256 + ord(str1[1]) - 65536
if asc >= -20319 and asc <= -20284:
return 'a'
if asc >= -20283 and asc <= -19776:
return 'b'
if asc >= -19775 and asc <= -19219:
return 'c'
if asc >= -19218 and asc <= -18711:
return 'd'
if asc >= -18710 and asc <= -18527:
return 'e'
if asc >= -18526 and asc <= -18240:
return 'f'
if asc >= -18239 and asc <= -17923:
return 'g'
if asc >= -17922 and asc <= -17418:
return 'h'
if asc >= -17417 and asc <= -16475:
return 'j'
if asc >= -16474 and asc <= -16213:
return 'k'
if asc >= -16212 and asc <= -15641:
return 'l'
if asc >= -15640 and asc <= -15166:
return 'm'
if asc >= -15165 and asc <= -14923:
return 'n'
if asc >= -14922 and asc <= -14915:
return 'o'
if asc >= -14914 and asc <= -14631:
return 'p'
if asc >= -14630 and asc <= -14150:
return 'q'
if asc >= -14149 and asc <= -14091:
return 'r'
if asc >= -14090 and asc <= -13119:
return 's'
if asc >= -13118 and asc <= -12839:
return 't'
if asc >= -12838 and asc <= -12557:
return 'w'
if asc >= -12556 and asc <= -11848:
return 'x'
if asc >= -11847 and asc <= -11056:
return 'y'
if asc >= -11055 and asc <= -10247:
return 'z'
return ''

主要的原理是GBK汉字是按拼音顺序编码的。