Metacharacters

Question 1

What does . metacharacter match?

Answer 1

any single character except for a newline character “(\n)”

Question 2

What does + metacharacter match?

Answer 2

one or more occurrences of the preceding character or group

Question 3

Which symbol denotes the start of a line or string?

Answer 3

^

Question 4

What does \w match?

Answer 4

• any word character, which includes alphanumeric characters (letters and digits) as well as underscores _
• equivalent to the character class [A-Za-z0-9_]

Question 5

What does \s match?

Answer 5

any whitespace character, which includes spaces, tabs, and newline characters

Question 6

What does \D match?

Answer 6

any character that is not a digit - negation of \d

Question 7

What does \d match?

Answer 7

any digit, which is equivalent to the character class [0-9]; represents a single numeric digit from 0 to 9

Question 8

What is the role of parentheses () in regular expressions?

Answer 8

primarily used for grouping, capturing, and controlling the precedence of subpatterns within a larger pattern

Question 9

How are parentheses () used for grouping?

Answer 9

• useful when there is a need to apply a quantifier (e.g., *, +, ?, {}) to a specific group of characters
• helps to ensure that all grouped elements are treated as a single unit within a pattern

(abc){2}

Question 10

What are word characters?

Answer 10

includes [A-Za-z0-9_]

Question 11

What does \w+ mean?

Answer 11

one or more characters are being matched

Question 12

What does .* match?

Answer 12

any character (except newlines) zero or more times