Python: Split unicode string on word boundaries

Question

I need to take a string, and shorten it to 140 characters.

Currently I am doing:

if len(tweet) > 140:
    tweet = re.sub(r\"\\s+\", \" \", tweet)          


        

Answer 1

Save two characters and use an elipsis (…, 0x2026) instead of three dots!

Answer 2

This punts the word-breaking decision to the re module, but it may work well enough for you.

import re

def shorten(tweet, footer="", limit=140):
    """Break tweet into two pieces at roughly the last word break
    before limit.
    """
    lower_break_limit = limit / 2
    # limit under which to assume breaking didn't work as expected

    limit -= len(footer)

    tweet = re.sub(r"\s+", " ", tweet.strip())
    m = re.match(r"^(.{,%d})\b(?:\W|$)" % limit, tweet, re.UNICODE)
    if not m or m.end(1) < lower_break_limit:
        # no suitable word break found
        # cutting at an arbitrary location,
        # or if len(tweet) < lower_break_limit, this will be true and
        # returning this still gives the desired result
        return tweet[:limit] + footer
    return m.group(1) + footer

Answer 3

Basically, in CJK (Except Korean with spaces), you need dictionary look-ups to segment words properly. Depending on your exact definition of "word", Japanese can be more difficult than that, since not all inflected variants of a word (i.e. "行こう" vs. "行った") will appear in the dictionary. Whether it's worth the effort depends upon your application.