Ch 8 (Twitter) Practice: Sentiment Analysis and Loop Variables

Now it’s your turn to practice sentiment analysis and loop variables

Sentiment Analyasis

First run the code to load up the Sentiment Intensity Analyzer

import nltk
nltk.download(["vader_lexicon"])
from nltk.sentiment import SentimentIntensityAnalyzer
sia = SentimentIntensityAnalyzer()

[nltk_data] Downloading package vader_lexicon to
[nltk_data]     C:\Users\kmthayer\AppData\Roaming\nltk_data...
[nltk_data]   Package vader_lexicon is already up-to-date!

Also, look at this example from the demo of running sentiment analysis:

sentence = "I love love love pizza!!!!!!!!"
sia.polarity_scores(sentence)["compound"]

0.941

Now, copy that two lines of code above, and try out your own sentences, and run the sentiment analysis on them

sentence = "This is an ok example"
sia.polarity_scores(sentence)["compound"]

0.296

Try several sentences and see how the Sentiment Intensity Analyzer handles them

sentence = "This is a horrible example"
sia.polarity_scores(sentence)["compound"]

-0.5423

Loop variables

Now let’s practice with loop variables.

Below is a for loop which goes through each letter in the word “Mississipi”.

for letter in "Mississipi":
    print(letter)

M
i
s
s
i
s
s
i
p
i

Make another copy of that loop, but add a variable before the loop called num_letters and use it count how many letters were in the word “Mississipi”. At the end display the number of letters.

num_letters = 0

for letter in "Mississipi":
    print(letter)
    num_letters += 1
    
print("There were " + str(num_letters) + " letters")

M
i
s
s
i
s
s
i
p
i
There were 10 letters

Make another copy of what you just did, but this time also count the number of “i”s. Make a variable called num_i to count how many “i”s.

Hint: To see if a letter is an “i”, check if letter == "i"

At the end print out how many of the letters were “i”s and what percentage of the word was “i”s.

num_letters = 0
num_i = 0

for letter in "Mississipi":
    print(letter)
    num_letters += 1
    
    if(letter == "i"):
        num_i += 1
    
print("There were " + str(num_letters) + " letters")

percent_i = num_i / num_letters * 100

print("i's made up " + str(percent_i) + " percent of the word")

M
i
s
s
i
s
s
i
p
i
There were 10 letters
i's made up 40.0 percent of the word