如何使用 Python 识别二进制和文本文件？
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How to identify binary and text files using Python?
提问by Thomas
I need identify which fileis binaryand which is a textin a directory.
我需要确定哪个文件是二进制文件，哪个是目录中的文本。
I tried use mimetypesbut it isnt a good idea in my case because it cant identify all files mimes, and I have strangers ones here... I just need know, binary or text. Simple ? But I couldn′t find a solution...
我尝试使用mimetypes，但在我的情况下这不是一个好主意，因为它无法识别所有文件 mime，而且我这里有陌生人......我只需要知道，二进制或文本。简单的 ？但我找不到解决方案......
Thanks
谢谢
采纳答案by Thomas
Thanks everybody, I found a solution that suited my problem. I found this code at http://code.activestate.com/recipes/173220/and I changed just a little piece to suit me.
谢谢大家，我找到了一个适合我的问题的解决方案。我在http://code.activestate.com/recipes/173220/找到了这段代码，我只更改了一小部分以适合我。
It works fine.
它工作正常。
from __future__ import division
import string
def istext(filename):
s=open(filename).read(512)
text_characters = "".join(map(chr, range(32, 127)) + list("\n\r\t\b"))
_null_trans = string.maketrans("", "")
if not s:
# Empty files are considered text
return True
if "import subprocess
import re
def is_text(fn):
msg = subprocess.Popen(["file", fn], stdout=subprocess.PIPE).communicate()[0]
return re.search('text', msg) != None
" in s:
# Files with null bytes are likely binary
return False
# Get the non-text characters (maps a character to itself then
# use the 'remove' option to get rid of the text characters.)
t = s.translate(_null_trans, text_characters)
# If more than 30% non-text characters, then
# this is considered a binary file
if float(len(t))/float(len(s)) > 0.30:
return False
return True
回答by Jon Skeet
It's inherently notsimple. There's no way of knowing for sure, although you can take a reasonably good guess in most cases.
它本质上并不简单。虽然在大多数情况下您可以做出合理的猜测，但无法确定。
Things you might like to do:
您可能喜欢做的事情：
- Look for known magic numbers in binary signatures
- Look for the Unicode byte-order-mark at the start of the file
- If the file is regularly 00 xx 00 xx 00 xx (for arbitrary xx) or vice versa, that's quite possibly UTF-16
- Otherwise, look for 0s in the file; a file with a 0 in is unlikelyto be a single-byte-encoding text file.
- 在二进制签名中查找已知的幻数
- 在文件开头查找 Unicode 字节顺序标记
- 如果文件经常是 00 xx 00 xx 00 xx（对于任意 xx）或反之亦然，那很可能是 UTF-16
- 否则，在文件中查找 0；带有 0 in 的文件不太可能是单字节编码的文本文件。
But it's all heuristic - it's quite possible to have a file which is a valid text file anda valid image file, for example. It would probably be nonsense as a text file, but legitimate in some encoding or other...
但这都是启发式的 - 例如，很有可能有一个文件是有效的文本文件和有效的图像文件。作为文本文件，它可能是无稽之谈，但在某些编码或其他方面是合法的......
回答by John Paulett
It might be possible to use libmagicto guess the MIME type of the file using python-magic. If you get back something in the "text/*"namespace, it is likely a text file, while anything else is likely a binary file.
可以使用libmagic猜测使用python-magic的文件的 MIME 类型。如果你在“text/*”命名空间中得到一些东西，它可能是一个文本文件，而其他任何东西都可能是一个二进制文件。
回答by Aoife
If your script is running on *nix, you could use something like this:
如果您的脚本在 *nix 上运行，您可以使用以下内容：
##代码##