You want to create a predicate method valid_name? that returns true only if a string is not empty and contains only letters. Which implementation is correct?
hard📝 Application Q15 of 15
Ruby - Methods
You want to create a predicate method valid_name? that returns true only if a string is not empty and contains only letters. Which implementation is correct?
Adef valid_name?(name)
name.nil? && name.match?(/[a-z]/)
end
Bdef valid_name?(name)
name.empty? || name.match?(/\d+/)
end
Cdef valid_name?(name)
name.length > 0 && name.include?(' ')
end
Ddef valid_name?(name)
!name.empty? && name.match?(/^[a-zA-Z]+$/)
end
Step-by-Step Solution
Solution:
Step 1: Understand the requirements
The method must return true only if the string is not empty and contains only letters.
Step 2: Evaluate each option
def valid_name?(name)
!name.empty? && name.match?(/^[a-zA-Z]+$/)
end checks that name is not empty and matches only letters using regex /^[a-zA-Z]+$/. This meets the requirements.
Final Answer:
def valid_name?(name)
!name.empty? && name.match?(/^[a-zA-Z]+$/)
end -> Option D
Quick Check:
Not empty and only letters = valid_name? true [OK]
Quick Trick:Use regex and empty? to validate strings in predicates [OK]
Common Mistakes:
Using || instead of && for conditions
Checking for digits instead of letters
Ignoring empty string check
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