Comment by akx

9 hours ago

This doesn't do the same thing though, since it's not Unicode aware.

    >>> 'x\u2009   a'.split()
    ['x', 'a']
    # incorrect; in bytes mode, `\S` doesn't know about unicode whitespace
    >>> list(re.finditer(br'\S+', 'x\u2009   a'.encode()))
    [<re.Match object; span=(0, 4), match=b'x\xe2\x80\x89'>, <re.Match object; span=(7, 8), match=b'a'>]
    # correct, in unicode mode
    >>> list(re.finditer(r'\S+', 'x\u2009   a'))
    [<re.Match object; span=(0, 1), match='x'>, <re.Match object; span=(5, 6), match='a'>]

5 comments

akx

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contravariant  9 hours ago

There's bound to be a way to turn a stream of bytes into a stream of unicode code points (at least I think that's what python is doing for strings). Though I'm explicitly not volunteering to write the code for it.

  • est  6 hours ago 

        import mmap, codecs

    from collections import Counter

    def word_count(filepath):

        freq = Counter()
    
        decode = codecs.getincrementaldecoder('utf-8')().decode
    
        with open(filepath, 'rb') as f, mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ) as mm:
        
                for chunk in iter(lambda: mm.read(65536), b''):
            
                        freq.update(decode(chunk).split())
            
                    freq.update(decode(b'', final=True).split())
        
                return freq

  • zahlman  6 hours ago

    Sure, but making one string from the file contents is surely much better than having a separate string per word in the original data.

    ... Ah, but I suppose the existing code hasn't avoided that anyway. (It's also creating regex match objects, but those get disposed each time through the loop.) I don't know that there's really a way around that. Given the file is barely a KB, I rather doubt that the illustrated techniques are going to move the needle.

    In fact, it looks as though the entire data structure (whether a dict, Counter etc.) should a relatively small part of the total reported memory usage. The rest seems to be internal Python stuff.