Word frequency analysis in Data Analysis Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of word frequency count using Counter

What is the output of this Python code that counts word frequencies in a list?

Data Analysis Python

from collections import Counter
words = ['apple', 'banana', 'apple', 'orange', 'banana', 'apple']
freq = Counter(words)
print(freq)

A Counter({'apple': 3, 'banana': 2, 'orange': 1})

B {'apple': 3, 'banana': 2, 'orange': 1}

C Counter({'apple': 2, 'banana': 2, 'orange': 2})

D {'apple': 2, 'banana': 2, 'orange': 1}

💡 Hint

Remember that Counter counts how many times each word appears.

Counter creates a dictionary-like object showing counts of each word. 'apple' appears 3 times, 'banana' 2 times, and 'orange' once.

❓ data_output

intermediate

Number of unique words in a text

Given this list of words, how many unique words are there?

Data Analysis Python

words = ['data', 'science', 'data', 'analysis', 'science', 'python', 'python', 'python']
unique_words = len(set(words))
print(unique_words)

A 8

B 3

C 5

D 4

💡 Hint

Use set to find unique items in a list.

The unique words are 'data', 'science', 'analysis', and 'python', so total 4.

❓ visualization

advanced

Bar chart of word frequencies

Which option shows the correct bar chart for the word frequencies in this data?

Data Analysis Python

import matplotlib.pyplot as plt
from collections import Counter
words = ['cat', 'dog', 'cat', 'bird', 'dog', 'dog']
counter = Counter(words)
plt.bar(counter.keys(), counter.values())
plt.show()

A Bar chart with bars: cat=3, dog=2, bird=1

B Bar chart with bars: cat=2, dog=3, bird=1

C Bar chart with bars: cat=1, dog=2, bird=3

D Bar chart with bars: cat=2, dog=2, bird=2

💡 Hint

Count how many times each word appears before plotting.

The word 'dog' appears 3 times, 'cat' 2 times, and 'bird' once, so the bar heights match these counts.

🔧 Debug

advanced

Identify the error in word frequency code

What error does this code raise when counting word frequencies?

Data Analysis Python

words = ['red', 'blue', 'red', 'green']
freq = {}
for word in words:
    freq[word] += 1
print(freq)

A SyntaxError

B TypeError

C KeyError

D No error, prints correct counts

💡 Hint

Check what happens when you try to add to a dictionary key that does not exist yet.

The dictionary freq is empty initially, so freq[word] += 1 tries to add to a missing key, causing KeyError.

🚀 Application

expert

Find the most frequent word in a large text

Given a large text split into words, which code snippet correctly finds the most frequent word?

Data Analysis Python

text = 'data science is fun and data science is powerful and data is everywhere'
words = text.split()

A

from collections import Counter
counter = Counter(words)
most_common = counter.most_common(1)[0][0]
print(most_common)

B

freq = {}
for w in words:
    freq[w] = freq.get(w, 0) + 1
most_common = max(freq)
print(most_common)

C

from collections import Counter
counter = Counter(words)
most_common = max(counter)
print(most_common)

D

freq = {}
for w in words:
    freq[w] = freq.get(w, 0) + 1
most_common = max(freq.values())
print(most_common)

💡 Hint

Use Counter's most_common method to get the word with highest count.

Option A uses Counter and most_common(1) to get the word with highest frequency. Other options either find max key or max count but do not get the word correctly.