Basic Syntax

Question 1

\Q…\E

For example: \Q+-*/\E

Answer 1

Matches the characters literally, suppressing the meaning of special characters.

For example, match +-*/

Question 2

\a

Answer 2

Matches the bell character

Question 3

\e

Answer 3

Matches the escape character

Question 4

\f

Answer 4

Matches the form feed character

Question 5

\v

Answer 5

Matches the vertical tab character

Question 6

[ ]

Answer 6

Symbol(s) used to encapsulate a character class. A character class matches a single character out of all the possibilities offered by the character class.

Question 7

^ immediately following a [

Answer 7

Negates the character class, causing it to match a single character not listed in the character class.

Question 8

\d

Answer 8

Matches a digit

Question 9

\w

Answer 9

Matches word characters (letters, digits and underscores)

Question 10

\s

Answer 10

Matches whitespace (spaces, tabs and linebreaks)

Question 11

\D

Answer 11

Matches a character that is not a digit

Question 12

\W

Answer 12

Matches a character that is not a word character (letters, digits, and underscores)

Question 13

\S

Answer 13

Matches a character that is not a whitespace

Question 14

\b

Answer 14

Matches a backspace character (inside a character class [ ] )

Question 15

\t

Answer 15

Matches a tab character (inside a character class [ ] )

Question 16

. (dot)

Answer 16

Matches any single character except line break characters

Question 17

\n

Answer 17

Matches a line break character

Answer 18

Matches at the start of the string the regex pattern is applied to

Question 19

$

Answer 19

Matches at the end of the string the regex pattern is applied to.

Question 20

\b

Answer 20

Matches at the position between a word character (anything matched by \w) and a non-word character (anything matched by [^\w] or \W) as well as at the start and/or end of the string if the first and/or last characters in the string are word characters.

Question 21

\B

Answer 21

Matches at the position between two word characters (i.e the position between \w\w) as well as at the position between two non-word characters (i.e. \W\W).

Question 22

(pipe)

Answer 22

Causes the regex engine to match either the part on the left side.

Question 23

?

Answer 23

Makes the preceding item optional.

Question 24

*

Answer 24

Repeats the previous item zero or more times.

Question 25

+

Answer 25

Repeats the previous item once or more.

Question 26

{n} where n is an integer >= 1

Answer 26

Repeats the previous item exactly n times.

Question 27

{n,m} where n >= 0 and m >= n

Answer 27

Repeats the previous item between n and m times.

Question 28

{n,} where n >= 0

Answer 28

Repeats the previous item at least n times.

Question 29

\1 through \9

Answer 29

Matches backreferences (previous sets of expressions enclosed in parentheses)

Question 30

\G

Answer 30

Matches at the position where the previous match ended, or the position where the current match attempt started.

Question 31

(?#comment)

Answer 31

Creates comments in a regular expression