English (English)
Alphabet used in regular expressions
A regular expression is a formal description of the structure of a word or a field value.
| 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". |
|
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 | [\\] |
Examples of regular expressions:
- Postal code: [0-9]{6}
An sample value: "142172" - Zip code (USA): [0-9]{5}("-"[0-9]{4}){-1}
Sample values: "55416", "33701-4313" - Income: N{4-8}[,]N{2}
Sample values: "15000,00", "4499,00" - Month in the numerical form: ((|"0")[1-9])|("10")|("11")|("12")
Sample values: "4", "05", "12" - Fraction: ("-"|)([0-9]{1-})(|(("."|",")([0-9]{1-})))
Sample values: "1234,567", "0.99", "100,0", "-345.6788903" - E-mail: [A-Za-z0-9_]{1-}(("."|"-")[A-Za-z0-9_]{1-}){-3}"@"[A-Za-z0-9_]{1-}(("."|"-")[A-Za-z0-9_]{1-}){-4}"."([A-Za-z]{2-4}|"asia"|"museum"|"travel"|"example"|"localhost"
Sample values: "support@abbyy.com", "my-name@company.org.ru", "info@gallery.museum"
See also:
12.04.2024 18:16:02