我有一个字符串,我想用它作为文件名,所以我想用Python删除文件名中不允许的所有字符。
我宁愿严格一点,所以假设我想只保留字母、数字和一小组其他字符,如“_-.()”。”。最优雅的解决方案是什么?
文件名需要在多个操作系统(Windows, Linux和Mac OS)上有效——它是我库中的一个MP3文件,以歌曲标题为文件名,并在3台机器之间共享和备份。
我有一个字符串,我想用它作为文件名,所以我想用Python删除文件名中不允许的所有字符。
我宁愿严格一点,所以假设我想只保留字母、数字和一小组其他字符,如“_-.()”。”。最优雅的解决方案是什么?
文件名需要在多个操作系统(Windows, Linux和Mac OS)上有效——它是我库中的一个MP3文件,以歌曲标题为文件名,并在3台机器之间共享和备份。
当前回答
这是Windows特定路径的另一个答案,使用简单的替换,没有时髦的模块:
import re
def check_for_illegal_char(input_str):
# remove illegal characters for Windows file names/paths
# (illegal filenames are a superset (41) of the illegal path names (36))
# this is according to windows blacklist obtained with Powershell
# from: https://stackoverflow.com/questions/1976007/what-characters-are-forbidden-in-windows-and-linux-directory-names/44750843#44750843
#
# PS> $enc = [system.Text.Encoding]::UTF8
# PS> $FileNameInvalidChars = [System.IO.Path]::GetInvalidFileNameChars()
# PS> $FileNameInvalidChars | foreach { $enc.GetBytes($_) } | Out-File -FilePath InvalidFileCharCodes.txt
illegal = '\u0022\u003c\u003e\u007c\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\u0008' + \
'\u0009\u000a\u000b\u000c\u000d\u000e\u000f\u0010\u0011\u0012\u0013\u0014\u0015' + \
'\u0016\u0017\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f\u003a\u002a\u003f\u005c\u002f'
output_str, _ = re.subn('['+illegal+']','_', input_str)
output_str = output_str.replace('\\','_') # backslash cannot be handled by regex
output_str = output_str.replace('..','_') # double dots are illegal too, or at least a bad idea
output_str = output_str[:-1] if output_str[-1] == '.' else output_str # can't have end of line '.'
if output_str != input_str:
print(f"The name '{input_str}' had invalid characters, "
f"name was modified to '{output_str}'")
return output_str
当测试check_for_illegal_char('fas\u0003\u0004good\\..asd.'),我得到:
The name 'fas♥♦good\..asd.' had invalid characters, name was modified to 'fas__good__asd'
其他回答
你可以看看Django框架(但要考虑到许可!),看看他们如何从任意文本中创建一个“slug”。段代码是URL和文件名友好的。
Django文本utils定义了一个函数,slugify(),这可能是这种事情的黄金标准。本质上,他们的代码如下。
import unicodedata
import re
def slugify(value, allow_unicode=False):
"""
Taken from https://github.com/django/django/blob/master/django/utils/text.py
Convert to ASCII if 'allow_unicode' is False. Convert spaces or repeated
dashes to single dashes. Remove characters that aren't alphanumerics,
underscores, or hyphens. Convert to lowercase. Also strip leading and
trailing whitespace, dashes, and underscores.
"""
value = str(value)
if allow_unicode:
value = unicodedata.normalize('NFKC', value)
else:
value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore').decode('ascii')
value = re.sub(r'[^\w\s-]', '', value.lower())
return re.sub(r'[-\s]+', '-', value).strip('-_')
旧版本是:
def slugify(value):
"""
Normalizes string, converts to lowercase, removes non-alpha characters,
and converts spaces to hyphens.
"""
import unicodedata
value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore')
value = unicode(re.sub('[^\w\s-]', '', value).strip().lower())
value = unicode(re.sub('[-\s]+', '-', value))
# ...
return value
还有更多,但我把它省略了,因为它没有解决怠惰,而是逃避。
仍然没有找到一个好的库来生成有效的文件名。注意,在德语、挪威语或法语等语言中,文件名中的特殊字符非常常见,完全可以接受。所以我最终有了自己的图书馆:
# util/files.py
CHAR_MAX_LEN = 31
CHAR_REPLACE = '_'
ILLEGAL_CHARS = [
'#', # pound
'%', # percent
'&', # ampersand
'{', # left curly bracket
'}', # right curly bracket
'\\', # back slash
'<', # left angle bracket
'>', # right angle bracket
'*', # asterisk
'?', # question mark
'/', # forward slash
' ', # blank spaces
'$', # dollar sign
'!', # exclamation point
"'", # single quotes
'"', # double quotes
':', # colon
'@', # at sign
'+', # plus sign
'`', # backtick
'|', # pipe
'=', # equal sign
]
def generate_filename(
name, char_replace=CHAR_REPLACE, length=CHAR_MAX_LEN,
illegal=ILLEGAL_CHARS, replace_dot=False):
''' return clean filename '''
# init
_elem = name.split('.')
extension = _elem[-1].strip()
_length = length - len(extension) - 1
label = '.'.join(_elem[:-1]).strip()[:_length]
filename = ''
# replace '.' ?
if replace_dot:
label = label.replace('.', char_replace)
# clean
for char in label + '.' + extension:
if char in illegal:
char = char_replace
filename += char
return filename
generate_虚构(“nucgae zutaaer .0.1 docx”,replace_dot=False)
nucgae_zutaäer..0.1.docx
generate_虚构(“nucgae zutaaer .0.1 docx”,replace_dot=True)
nucgae_zutaäer__0_1.docx
大多数解决方案都不起作用。
“你好/世界”——>“你好世界”
“/helloworld”/ ->“helloworld”
这通常不是你想要的,比如说你要为每个链接保存html,你要为不同的网页覆盖html。
我腌字典,如:
{'helloworld':
(
{'/hello/world': 'helloworld', '/helloworld/': 'helloworld1'},
2)
}
2表示应该追加到下一个文件名的数字。
我每次都从字典中查找文件名。如果它不在那里,我创建一个新的,如果需要追加最大的数字。
>>> import string
>>> safechars = bytearray(('_-.()' + string.digits + string.ascii_letters).encode())
>>> allchars = bytearray(range(0x100))
>>> deletechars = bytearray(set(allchars) - set(safechars))
>>> filename = u'#ab\xa0c.$%.txt'
>>> safe_filename = filename.encode('ascii', 'ignore').translate(None, deletechars).decode()
>>> safe_filename
'abc..txt'
它不处理空字符串,特殊文件名('nul', 'con'等)。
This whitelist approach (ie, allowing only the chars present in valid_chars) will work if there aren't limits on the formatting of the files or combination of valid chars that are illegal (like ".."), for example, what you say would allow a filename named " . txt" which I think is not valid on Windows. As this is the most simple approach I'd try to remove whitespace from the valid_chars and prepend a known valid string in case of error, any other approach will have to know about what is allowed where to cope with Windows file naming limitations and thus be a lot more complex.
>>> import string
>>> valid_chars = "-_.() %s%s" % (string.ascii_letters, string.digits)
>>> valid_chars
'-_.() abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
>>> filename = "This Is a (valid) - filename%$&$ .txt"
>>> ''.join(c for c in filename if c in valid_chars)
'This Is a (valid) - filename .txt'