Regular expressions

Name

Conventional designation

Usage example

Any character

*

“c”*“t” – allows such words as cat, cot, etc.

Letter

C

C”ot” – allows such words as Rot, pot, cot, Dot, mot, etc.

Uppercase letter

A

A”ot” – allows such words as Rot, Cot, Mot, Dot, etc.

Lowercase letter

a

a”ot” – allows such words as rot, cot, mot, dot, etc.

Letter or number

X

X – allows any standalone number or letter.

Number

N

N”th” allows such words as 5th, 4th, 6th, etc.

String

” "

"cot”

Or

|

“pl”(“o”|“a”)“t” – allows words “plot” and “plat”.

Character from group

[]

[tm]“ot” – allows words “tot” and “mot”.

Character not from group

[^]

[^t]“ot” – allows words “cot”, “lot”, etc., but does not allow the word “tot”.

Space (within group)

\s

[A\s] allows only the letter A or a space.

Any number of repetitions

(applies to the expression or subexpression on the left)

{-}

[AB74]{-} – allows any combinations of characters A, B, 7, 4 of any length.

Number of repetitions n

{n}

N{2}“th” allows such words as 25th, 84th, 11th, etc.

From n to m repetitions

{n-m}

N{1-3}“th” allows such words as 5th, 84th, 111th, etc.

From 0 to n repetitions

{-n}

N{-2}“th” allows such words as 84th, 5th, etc.

From n repetitions and more

{n-}

N{2-}“th” allows such words as 25th, 834th, 311th, 34576th, etc.

Subexpression

()

Hyphen symbol

[\-]

Slash symbol

[\\]