Core Java Programming Course- Quantifiers in RegEx (regular expressions)

The video tutorial explains the use of quantifiers in regular expressions, focusing on asterisk (*), plus (+), question mark (?), and curly brackets {}. Each quantifier is discussed in terms of its function in matching preceding characters or blocks of characters. The tutorial provides examples and explains how to use these quantifiers to specify the number of repetitions in a pattern, making it easier to match strings in Java and other programming languages.

What is the primary purpose of quantifiers in regular expressions?

• To match a single character

• To match multiple occurrences of a character or block

• To replace characters in a string

• To define a new character set

How does the * quantifier function in a regular expression?

• It matches the preceding character zero or more times

• It matches the preceding character exactly once

• It makes the preceding character optional

• It matches the preceding character one or more times

What will the * quantifier return if the preceding character is absent in the string?

• A warning

• An error

• True

• False

What is the key difference between the * and + quantifiers?

• * requires at least one occurrence, + does not

• + requires at least one occurrence, * does not

• + matches exactly once, * matches zero or more times

• * matches exactly once, + matches zero or more times

In what scenario will the + quantifier return false?

• When the preceding character is present once

• When the preceding character is absent

• When the preceding character is optional

• When the preceding character is present multiple times

What does the ? quantifier do in a regular expression?

• Makes the preceding character optional

• Matches the preceding character exactly twice

• Matches the preceding character zero or more times

• Matches the preceding character one or more times

How does the ? quantifier affect the matching of a character?

• It requires the character to appear at least once

• It allows the character to appear zero or one time

• It allows the character to appear any number of times

• It requires the character to appear twice

What do curly brackets specify in a regular expression?

• The exact number of repetitions

• The type of quantifier to be applied

• The character set to be used

• The position of the character

How can you specify a range of repetitions using curly brackets?

• By using a question mark

• By using a single number

• By using a comma between two numbers

• By using a plus sign

What does leaving the maximum value blank in curly brackets signify?

• The character must not appear

• The character can appear any number of times

• The character must appear exactly twice

• The character must appear exactly once