Removing escaped entities from a String in Python [duplicate]

问题

I've a huge csv file of tweets. I read them both into the computer and stored them in two separate dictionaries - one for negative tweets, one for positive. I wanted to read the file in and parse it to a dictionary whilst removing any punctuation marks. I've used this code:

tweets = []
for (text, sentiment) in pos_tweets.items() + neg_tweets.items():
    shortenedText = [e.lower() and e.translate(string.maketrans("",""), string.punctuation) for e in text.split() if len(e) >= 3 and not e.startswith('http')]
print shortenedText

It's all worked well barring one minor problem. The huge csv file I've downloaded has unfortunately changed some of the punctuation. I'm not sure what this is called so can't really google it, but effectively some sentence might begin:

"ampampFightin"
"&quot;The truth is out there"
"&altThis is the way I feel"

Is there a way to get rid of all these? I notice the latter two begin with an ampersand - will a simple search for that get rid of it (the only reason I'm asking and not doing is because there's too many tweets for me to manually check)

回答1:

First, unescape HTML entities, then remove punctuation chars:

import HTMLParser

tweets = []
for (text, sentiment) in pos_tweets.items() + neg_tweets.items():
    text = HTMLParser.HTMLParser().unescape(text)
    shortenedText = [e.lower() and e.translate(string.maketrans("",""), string.punctuation) for e in text.split() if len(e) >= 3 and not e.startswith('http')]
print shortenedText

Here's an example, how unescape works:

>>> import HTMLParser
>>> HTMLParser.HTMLParser().unescape("&quot;The truth is out there")
u'"The truth is out there'

UPD: the solution to UnicodeDecodeError problem : use text.decode('utf8'). Here's a good explanation why do you need to do this.

来源：https://stackoverflow.com/questions/18146557/removing-escaped-entities-from-a-string-in-python

标签

python

string

punctuation