Special characters

Question 1

.

Answer 1

matches any single character except line terminators

Question 2

\d

Answer 2

matches any digit === [0-9]

Question 3

\D

Answer 3

matches any non digit

Question 4

\w

Answer 4

matches any alphanumeric character from basic latin alphabet including underscore

Question 5

\W

Answer 5

matches any character that is not a word character from the basic latin alphabet

Question 6

\s

Answer 6

matches a single white space character

Question 7

\S

Answer 7

matches a single character other than white space

Question 8

\t

Answer 8

matches a horizontal tab

Question 9

\r

Answer 9

matches a carriage return

Question 10

\n

Answer 10

matches a linefeed

Question 11

\v

Answer 11

matches a vertical tab

Question 12

\f

Answer 12

matches a form-feed

Question 13

[\b]

Answer 13

matches a backspace

Question 14

\0

Answer 14

matches a NUL character

Question 15

\cX

Answer 15

where X is a letter from A-Z, matches a control character in a string

Question 16

\xhh

Answer 16

matches the character with code hh(two hexadecimal digits)

Question 17

\uhhhh

Answer 17

matches a UTF-16 code-unit with the value hhhh(four hexadecimal digits)

Question 18

\

Answer 18

indicates that the next character is special and not to be interpreted literally

Question 19

[xyz] [a-c]

Answer 19

matches any one of enclosed characters can specify range with hyphen, hyphen can be literal if at end

Question 20

[^xyz]

Answer 20

negated or complemented character set

Question 21

x|y

Answer 21

matches either x or y

Answer 22

matches beginning of input

Question 23

$

Answer 23

matches end of input

Question 24

\b

Answer 24

matches a word boundary (i.e start or end)

Question 25

\B

Answer 25

matches a non-word boundary

Question 26

(x)

Answer 26

matches x and remembers match, capturing groups

Question 27

\n

Answer 27

where n is positive integer, back reference to last substring matching the n

Question 28

(?:x)

Answer 28

matches x but does not remember, non capturing groups

Question 29

x*

Answer 29

matches the preceding item x 0 or more times

Question 30

x+

Answer 30

matches the preceding item x 1 or more times === {1,}

Question 31

x?

Answer 31

matches preceding item x 0 or 1 time

Question 32

x{n}

Answer 32

where n is a positive integer matches exactly n occurences of the preceding item x

Question 33

x{n,}

Answer 33

where n is a positive integer matches at least n occurences

Question 34

x{n,m}

Answer 34

matches at least n and at most m of x

Question 35

?

Answer 35

matches preceding item but smallest possible

Question 36

x(?=y)

Answer 36

matches x only if followed by y

Question 37

x(?!y)

Answer 37

matches x only if x is not followed by y

Question 38

compile()

Answer 38

compiles reg expression during execution of a script

Question 39

exex()

Answer 39

executes a search for a match in its string parameter

Question 40

test()

Answer 40

tests for a match in its string parameter

Question 41

match()

Answer 41

performs match to given string and returns match result

Question 42

replace()

Answer 42

replaces matches in given string with new substring

Question 43

search()

Answer 43

searches match in given string and returns index

Question 44

split()

Answer 44

splits given string into an array by separating the string into substring

Question 45

lastIndex

Answer 45

returns last index of reg expression