优雅的Python函数将CamelCase转换为snake_case？

Question

优雅的Python函数将CamelCase转换为snake_case？

例：

>>> convert('CamelCase')'camel_case'

Answer 1

这非常彻底：def convert(name):    s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)    return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()适用于所有这些（并且不会损害已经未出版的版本）：>>> convert('CamelCase')'camel_case'>>> convert('CamelCamelCase')'camel_camel_case'>>> convert('Camel2Camel2Case')'camel2_camel2_case'>>> convert('getHTTPResponseCode')'get_http_response_code'>>> convert('get2HTTPResponseCode')'get2_http_response_code'>>> convert('HTTPResponseCode')'http_response_code'>>> convert('HTTPResponseCodeXYZ')'http_response_code_xyz'或者，如果你打算多次调用它，你可以预编译正则表达式：first_cap_re = re.compile('(.)([A-Z][a-z]+)')all_cap_re = re.compile('([a-z0-9])([A-Z])')def convert(name):    s1 = first_cap_re.sub(r'\1_\2', name)    return all_cap_re.sub(r'\1_\2', s1).lower()不要忘记导入正则表达式模块import re

Answer 2

我不知道为什么这些都如此复杂。对于大多数情况，简单的表达式([A-Z]+)将起到作用>>> re.sub('([A-Z]+)', r'_\1','CamelCase').lower()'_camel_case'&nbsp;&nbsp;>>> re.sub('([A-Z]+)', r'_\1','camelCase').lower()'camel_case'>>> re.sub('([A-Z]+)', r'_\1','camel2Case2').lower()'camel2_case2'>>> re.sub('([A-Z]+)', r'_\1','camelCamelCase').lower()'camel_camel_case'>>> re.sub('([A-Z]+)', r'_\1','getHTTPResponseCode').lower()'get_httpresponse_code'要忽略第一个字符，只需在后面添加外观 (?!^)>>> re.sub('(?!^)([A-Z]+)', r'_\1','CamelCase').lower()'camel_case'>>> re.sub('(?!^)([A-Z]+)', r'_\1','CamelCamelCase').lower()'camel_camel_case'>>> re.sub('(?!^)([A-Z]+)', r'_\1','Camel2Camel2Case').lower()'camel2_camel2_case'>>> re.sub('(?!^)([A-Z]+)', r'_\1','getHTTPResponseCode').lower()'get_httpresponse_code'如果你想将ALLCaps分离到all_caps并期望你的字符串中的数字，你仍然不需要做两个单独的运行只需使用|这个表达式((?<=[a-z0-9])[A-Z]|(?!^)[A-Z](?=[a-z]))几乎可以处理书中的每个场景>>> a = re.compile('((?<=[a-z0-9])[A-Z]|(?!^)[A-Z](?=[a-z]))')>>> a.sub(r'_\1', 'getHTTPResponseCode').lower()'get_http_response_code'>>> a.sub(r'_\1', 'get2HTTPResponseCode').lower()'get2_http_response_code'>>> a.sub(r'_\1', 'get2HTTPResponse123Code').lower()'get2_http_response123_code'>>> a.sub(r'_\1', 'HTTPResponseCode').lower()'http_response_code'>>> a.sub(r'_\1', 'HTTPResponseCodeXYZ').lower()'http_response_code_xyz'这一切都取决于你想要什么，所以使用最适合你需求的解决方案，因为它不应该过于复杂。的nJoy！