Given an array words = ['cat', 'dog', 'cat', 'bird'], which Ruby code snippet correctly uses a hash with a default value to count the frequency of each word?

hard📝 Application Q8 of 15

Ruby - Hashes

Given an array words = ['cat', 'dog', 'cat', 'bird'], which Ruby code snippet correctly uses a hash with a default value to count the frequency of each word?

Acounts = Hash.new; words.each { |w| counts[w] = counts[w] + 1 }

Bcounts = Hash.new([]); words.each { |w| counts[w] += 1 }

Ccounts = Hash.new(0); words.each { |w| counts[w] += 1 }

Dcounts = {}; words.each { |w| counts[w] = 1 }

Step-by-Step Solution

Solution:

Step 1: Initialize hash with default 0
Using Hash.new(0) ensures missing keys return 0, allowing increment.
Step 2: Iterate and increment counts
For each word, increment the count by 1.
Final Answer:
counts = Hash.new(0); words.each { |w| counts[w] += 1 } -> Option C
Quick Check:
Check if missing keys start at 0 and increment correctly [OK]

Quick Trick: Use Hash.new(0) for counting frequencies [OK]

Common Mistakes:

Using Hash.new([]) which returns the same array for all keys
Not initializing default value, causing nil errors on increment
Assigning 1 to each key without incrementing counts

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More Ruby Quizzes

Given an array words = ['cat', 'dog', 'cat', 'bird'], which Ruby code snippet correctly uses a hash with a default value to count the frequency of each word?

Step 1: Initialize hash with default 0

Step 2: Iterate and increment counts

Final Answer:

Quick Check:

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