Ruby - Arrays
Given an array
arr = [1, 2, 3, 4, 5], which Ruby code correctly creates a new array with only even numbers?Given an array arr = [1, 2, 3, 4, 5], which Ruby code correctly creates a new array with only even numbers?
hard📝 Application Q15 of 15
Step-by-Step Solution
Solution:
Step 1: Understand the goal
We want a new array containing only even numbers from the original array.Step 2: Analyze each option
new_arr = arr.select { |num| num % 2 == 0 } uses 'select' to filter even numbers correctly. new_arr = arr.map { |num| num * 2 } doubles all numbers, not filtering. new_arr = arr.delete_if { |num| num.even? } deletes even numbers, opposite of goal. new_arr = arr.push(2, 4) adds 2 and 4 to original array, not filtering.Final Answer:
new_arr = arr.select { |num| num % 2 == 0 } -> Option DQuick Check:
Use 'select' to filter arrays [OK]
Quick Trick: Use 'select' to pick items matching a condition [OK]
Common Mistakes:
MISTAKES- Using 'map' instead of 'select' for filtering
- Deleting instead of selecting items
- Adding items instead of filtering
Master "Arrays" in Ruby
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