MCQs on Working with Strings and Numbers | Ruby

Master Ruby’s String and Number Manipulation with this comprehensive chapter on string basics, manipulation techniques, interpolation, concatenation, and number operations, including arithmetic, conversion, and comparison in Ruby.

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1. String Basics and Manipulation

1. What is the output of the following Ruby code: "Hello".length?
   • A) 5
   • B) “Hello”
   • C) 6
   • D) nil
2. How can you convert a string to lowercase in Ruby?
   • A) .downcase
   • B) .to_lower
   • C) .lowercase
   • D) .to_lowercase
3. Which method is used to check if a string contains a substring in Ruby?
   • A) .include?
   • B) .contains?
   • C) .has_substring?
   • D) .find_substring?
4. How do you remove leading and trailing spaces from a string in Ruby?
   • A) .strip
   • B) .trim
   • C) .clean
   • D) .clear
5. What is the result of "Ruby"[1..3] in Ruby?
   • A) “uby”
   • B) “Ru”
   • C) “ub”
   • D) “y”
6. How can you replace a substring in a Ruby string?
   • A) .sub
   • B) .replace
   • C) .change
   • D) .switch
7. What method can you use to check if a string is empty in Ruby?
   • A) .empty?
   • B) .is_empty?
   • C) .nil?
   • D) .blank?
8. How do you concatenate two strings in Ruby?
   • A) "hello" + "world"
   • B) "hello".concat("world")
   • C) Both A and B
   • D) concat("hello", "world")
9. Which method returns the index of a substring in a string in Ruby?
   • A) .index
   • B) .find
   • C) .locate
   • D) .search
10. What is the result of "Ruby"[0, 3]?
    • A) “Ruby”
    • B) “Rub”
    • C) “y”
    • D) “Ru”

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2. Interpolation and Concatenation

11. How is string interpolation performed in Ruby?
    • A) "Hello #{name}"
    • B) "Hello + name"
    • C) "Hello [name]"
    • D) "Hello {name}"
12. What is the output of the following Ruby code: name = "Alice"; "Hello #{name}"?
    • A) “Hello Alice”
    • B) “Hello #{name}”
    • C) “Hello”
    • D) “Alice”
13. What happens when you use the + operator to concatenate two strings in Ruby?
    • A) It returns a new string with both concatenated
    • B) It modifies the first string
    • C) It raises an error
    • D) It repeats the string
14. How do you insert a variable into a string in Ruby?
    • A) Use #{variable}
    • B) Use + variable
    • C) Use []
    • D) Use () variable
15. Which of the following is NOT a valid Ruby string concatenation method?
    • A) + operator
    • B) .concat
    • C) .append
    • D) .push
16. What does the << operator do in Ruby?
    • A) Adds a character to the end of a string
    • B) Subtracts characters from a string
    • C) Reverses the string
    • D) Finds a substring
17. How would you concatenate a string and a number in Ruby?
    • A) "Hello " + 5
    • B) "Hello " + "5"
    • C) "Hello" + 5.to_s
    • D) "Hello 5"
18. What is the output of "Hello" + " " + "World" in Ruby?
    • A) “HelloWorld”
    • B) “Hello World”
    • C) “Hello”
    • D) “WorldHello”
19. Which method is used to replace a substring within a string in Ruby?
    • A) .replace
    • B) .change
    • C) .sub
    • D) .interpolate
20. How do you insert a newline character in a string in Ruby?
    • A) \n
    • B) \t
    • C) \r
    • D) \b

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3. Number Operations (Arithmetic, Conversion, Comparison)

21. What is the result of 5 + 3 * 2 in Ruby?
    • A) 16
    • B) 11
    • C) 13
    • D) 23
22. How can you convert a string to an integer in Ruby?
    • A) .to_i
    • B) .to_int
    • C) .convert
    • D) .integer
23. What is the result of 10 / 3 in Ruby?
    • A) 3.333333
    • B) 3
    • C) 10
    • D) 3.0
24. Which method is used to round a number in Ruby?
    • A) .round
    • B) .floor
    • C) .ceil
    • D) .truncate
25. What is the output of 5 == 5 in Ruby?
    • A) false
    • B) true
    • C) 0
    • D) 1
26. Which operator checks if two numbers are equal in Ruby?
    • A) ==
    • B) ===
    • C) =
    • D) =
27. How do you perform floating-point division in Ruby?
    • A) Use /
    • B) Use //
    • C) Use %
    • D) Use .
28. What is the result of 3.5.to_i in Ruby?
    • A) 4
    • B) 3
    • C) 5
    • D) 3.5
29. What method would you use to convert a float to a string in Ruby?
    • A) .to_s
    • B) .convert
    • C) .to_str
    • D) .stringify
30. What is the result of 5 > 3 in Ruby?
    • A) false
    • B) true
    • C) 5
    • D) 3

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Answers

Qno	Answer
1	A) 5
2	A) .downcase
3	A) .include?
4	A) .strip
5	C) “ub”
6	A) .sub
7	A) .empty?
8	C) Both A and B
9	A) .index
10	B) “Rub”
11	A) "Hello #{name}"
12	A) “Hello Alice”
13	A) It returns a new string with both concatenated
14	A) Use #{variable}
15	D) .push
16	A) Adds a character to the end of a string
17	C) "Hello" + 5.to_s
18	B) “Hello World”
19	C) .sub
20	A) \n
21	B) 11
22	A) .to_i
23	B) 3
24	A) .round
25	B) true
26	A) ==
27	A) Use /
28	B) 3
29	A) .to_s
30	B) true