How to capture iterated output variable into list for analysis

Question

I am trying to parse html text from a number of webpages for sentiment analysis. With the help from community I have been able to iterate over many urls and produce sentiment score based on the textblob library's sentiment analysis and have used the print function successfully to output a score for each url. However I have not been able to achieve, putting the many outputs produced by my return variable into a list so I can use to continue my analysis further by using the stored numbers for calculating averages, and displaying my results in a graph later.

Code with print function:

import requests
import json
import urllib
from bs4 import BeautifulSoup
from textblob import TextBlob



#you can add to this
urls = ["http://www.thestar.com/business/economy/2015/05/19/canadian-consumer-confidence-dips-but-continues-to-climb-in-us-report.html",
        "http://globalnews.ca/news/2012054/canada-ripe-for-an-invasion-of-u-s-dollar-stores-experts-say/",
        "http://www.cp24.com/news/tsx-flat-in-advance-of-fed-minutes-loonie-oil-prices-stabilize-1.2381931",
        "http://www.marketpulse.com/20150522/us-and-canadian-gdp-to-close-out-week-in-fx/",
        "http://www.theglobeandmail.com/report-on-business/canada-pension-plan-fund-sees-best-ever-annual-return/article24546796/",
        "http://www.marketpulse.com/20150522/canadas-april-inflation-slowest-in-two-years/"]


def parse_websites(list_of_urls):
    for url in list_of_urls:
        html = urllib.urlopen(url).read()
        soup = BeautifulSoup(html)
        # kill all script and style elements

        for script in soup(["script", "style"]):
            script.extract()    # rip it out

        # get text
        text = soup.get_text()

        # break into lines and remove leading and trailing space on each
        lines = (line.strip() for line in text.splitlines())
        # break multi-headlines into a line each
        chunks = (phrase.strip() for line in lines for phrase in line.split("  "))
        # drop blank lines
        text = '\n'.join(chunk for chunk in chunks if chunk)

        #print(text)

        wiki = TextBlob(text)
        r = wiki.sentiment.polarity

        print r




parse_websites(urls)

output:

>>> 
0.10863027172
0.156074203574
0.0766585497835
0.0315555555556
0.0752548359411
0.0902824858757
>>> 

but when I use the return variable to form a list to use the values to work with I get no result, code:

import requests
import json
import urllib
from bs4 import BeautifulSoup
from textblob import TextBlob



#you can add to this
urls = ["http://www.thestar.com/business/economy/2015/05/19/canadian-consumer-confidence-dips-but-continues-to-climb-in-us-report.html",
        "http://globalnews.ca/news/2012054/canada-ripe-for-an-invasion-of-u-s-dollar-stores-experts-say/",
        "http://www.cp24.com/news/tsx-flat-in-advance-of-fed-minutes-loonie-oil-prices-stabilize-1.2381931",
        "http://www.marketpulse.com/20150522/us-and-canadian-gdp-to-close-out-week-in-fx/",
        "http://www.theglobeandmail.com/report-on-business/canada-pension-plan-fund-sees-best-ever-annual-return/article24546796/",
        "http://www.marketpulse.com/20150522/canadas-april-inflation-slowest-in-two-years/"]


def parse_websites(list_of_urls):
    for url in list_of_urls:
        html = urllib.urlopen(url).read()
        soup = BeautifulSoup(html)
        # kill all script and style elements

        for script in soup(["script", "style"]):
            script.extract()    # rip it out

        # get text
        text = soup.get_text()

        # break into lines and remove leading and trailing space on each
        lines = (line.strip() for line in text.splitlines())
        # break multi-headlines into a line each
        chunks = (phrase.strip() for line in lines for phrase in line.split("  "))
        # drop blank lines
        text = '\n'.join(chunk for chunk in chunks if chunk)

        #print(text)

        wiki = TextBlob(text)
        r = wiki.sentiment.polarity
        r = []
        return [r]




parse_websites(urls)

output:

Python 2.7.5 (default, May 15 2013, 22:43:36) [MSC v.1500 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> ================================ RESTART ================================
>>> 
>>> 

How can I make it so I can work with the numbers and be able to add, subtract, them from list like so [r1, r2, r3...]

Thank you in advance.

Answer 1

From your code below, you are asking python to return an empty list:

r = wiki.sentiment.polarity

r = []     #creat empty list r
return [r] #return empty list

If I understood your issue correctly, all you have to do is:

my_list = [] #create empty list

   for url in list_of_urls:
    html = urllib.urlopen(url).read()
    soup = BeautifulSoup(html)

    for script in soup(["script", "style"]):
        script.extract()    # rip it out

    text = soup.get_text()

    lines = (line.strip() for line in text.splitlines())
    chunks = (phrase.strip() for line in lines for phrase in line.split("  "))
    text = '\n'.join(chunk for chunk in chunks if chunk)

    wiki = TextBlob(text)
    r = wiki.sentiment.polarity

    my_list.append(r) #add r to list my_list

print my_list

[r1, r2, r3, ...]

Alternatively, you could creat a dictionary with the url as the key

my_dictionary = {}

        r = wiki.sentiment.polarity
        my_dictionary[url] = r

print my_dictionary

{'url1': r1, 'url2 : r2, etc)

print my_dictionary['url1']

r1

A dictionary may make more sense for you, as it would be easier to retrieve, edit, and delete "r", using the url used as a key.

I am kind of new to Python, so hopefully others will correct me if this doesn't make sense...