PHP Regular Expressions MCQ

1. What function is used to perform a regular expression match in PHP?

a) preg_match()
b) reg_match()
c) match_regex()
d) regex()

Answer:

a) preg_match()

Explanation:

The preg_match() function is used for performing a regular expression match in PHP.

2. Which character is used as the delimiter in PHP regular expressions?

a) /
b) #
c) Both a) and b)
d) $

Answer:

c) Both a) and b)

Explanation:

In PHP, regular expressions are typically enclosed within delimiters like / or #.

3. How do you denote the beginning of a string in a PHP regular expression?

a) ^
b) $
c) *
d) +

Answer:

a) ^

Explanation:

The ^ character is used to denote the beginning of a string in regular expressions.

4. What does the '?' character represent in a PHP regular expression?

a) Zero or one occurrence of the preceding character
b) One or more occurrences of the preceding character
c) Exactly one occurrence of any character
d) Any number of occurrences of the preceding character

Answer:

a) Zero or one occurrence of the preceding character

Explanation:

In regular expressions, '?' denotes zero or one occurrence of the preceding character.

5. What is the role of the preg_replace() function in PHP?

a) To split a string by a regular expression
b) To check if a regular expression matches a string
c) To replace text in a string using a regular expression
d) To escape special characters in a regular expression

Answer:

c) To replace text in a string using a regular expression

Explanation:

preg_replace() is used to perform a search and replace with a regular expression.

6. Which metacharacter is used to represent any single character in a regular expression?

a) .
b) *
c) ?
d) +

Answer:

a) .

Explanation:

The '.' metacharacter is used to match any single character in regular expressions.

7. How do you denote the end of a string in a PHP regular expression?

a) ^
b) $
c) *
d) +

Answer:

b) $

Explanation:

The $ character is used to denote the end of a string in regular expressions.

8. What does the '*' character represent in a PHP regular expression?

a) Zero or one occurrence of the preceding character
b) One or more occurrences of the preceding character
c) Zero or more occurrences of the preceding character
d) Exactly one occurrence of any character

Answer:

c) Zero or more occurrences of the preceding character

Explanation:

In regular expressions, '*' denotes zero or more occurrences of the preceding character.

9. In PHP, how do you perform a case-insensitive regular expression match?

a) Using the 'i' modifier
b) Using the strtolower() function
c) Using the 'm' modifier
d) PHP regular expression matches are always case-insensitive

Answer:

a) Using the 'i' modifier

Explanation:

The 'i' modifier is used to perform a case-insensitive match in PHP regular expressions.

10. What does the '\d' metacharacter represent in a regular expression in PHP?

a) Any non-digit character
b) Any digit character
c) Any whitespace character
d) Any non-whitespace character

Answer:

b) Any digit character

Explanation:

In regular expressions, '\d' represents any digit character (0-9).

11. Which function is used to split a string by a regular expression in PHP?

a) preg_split()
b) preg_match()
c) split()
d) explode()

Answer:

a) preg_split()

Explanation:

The preg_split() function is used to split a string into an array using a regular expression as the delimiter.

12. What does the '|' character represent in PHP regular expressions?

a) And operator
b) Or operator
c) Concatenation
d) None of the above

Answer:

b) Or operator

Explanation:

The '|' character is used as the OR operator in regular expressions.

13. How do you escape special characters in a regular expression in PHP?

a) Using the preg_escape() function
b) Using the escape() function
c) By prefixing them with a backslash (\)
d) Special characters do not need to be escaped in PHP regular expressions

Answer:

c) By prefixing them with a backslash (\)

Explanation:

Special characters in regular expressions are escaped by prefixing them with a backslash.

14. What does the '+ 'character represent in a PHP regular expression?

a) Zero or one occurrence of the preceding character
b) One or more occurrences of the preceding character
c) Zero or more occurrences of the preceding character
d) Exactly one occurrence of any character

Answer:

b) One or more occurrences of the preceding character

Explanation:

In regular expressions, '+' denotes one or more occurrences of the preceding character.

15. Which regular expression pattern in PHP matches any whitespace character?

a) \s
b) \S
c) \w
d) \W

Answer:

a) \s

Explanation:

The '\s' metacharacter is used to match any whitespace character, including spaces, tabs, and line breaks.

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