How can you combine lazy enumerators with infinite sequences to find the first 4 prime numbers greater than 50?

hard📝 Application Q9 of 15

Ruby - Functional Patterns in Ruby

A(1..50).lazy.select { |n| prime?(n) }.first(4)

B(51..Float::INFINITY).lazy.select { |n| prime?(n) }.first(4)

C(50..100).lazy.select { |n| prime?(n) }.first(4)

D(51..Float::INFINITY).select { |n| prime?(n) }.first(4)

Step-by-Step Solution

Solution:

Step 1: Use infinite range starting after 50
Range from 51 to infinity lazily filtered for primes.
Step 2: Use lazy select and first(4)
Lazy select filters primes without computing all; first(4) gets first 4 primes > 50.
Step 3: Check other options
(1..50).lazy.select { |n| prime?(n) }.first(4) searches below 50; C is limited range; D is not lazy and infinite select causes hang.
Final Answer:
(51..Float::INFINITY).lazy.select { |n| prime?(n) }.first(4) -> Option B
Quick Check:
Lazy infinite prime filter = (51..Float::INFINITY).lazy.select { |n| prime?(n) }.first(4) [OK]

Quick Trick: Combine lazy with infinite range for filtered sequences [OK]

Common Mistakes:

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