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Ilya Kantor 2019-09-06 16:48:59 +03:00
parent 681cae4b6a
commit 4232a53219
10 changed files with 315 additions and 342 deletions
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22
9-regular-expressions/02-regexp-character-classes/article.md
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@ -13,9 +13,9 @@ For instance, the let's find the first digit in the phone number:
```js run
let str = "+7(903)-123-45-67";
let reg = /\d/;
let regexp = /\d/;
alert( str.match(reg) ); // 7
alert( str.match(regexp) ); // 7
```
Without the flag `pattern:g`, the regular expression only looks for the first match, that is the first digit `pattern:\d`.
@ -25,12 +25,12 @@ Let's add the `pattern:g` flag to find all digits:
```js run
let str = "+7(903)-123-45-67";
let reg = /\d/g;
let regexp = /\d/g;
alert( str.match(reg) ); // array of matches: 7,9,0,3,1,2,3,4,5,6,7
alert( str.match(regexp) ); // array of matches: 7,9,0,3,1,2,3,4,5,6,7
// let's make the digits-only phone number of them:
alert( str.match(reg).join('') ); // 79035419441
alert( str.match(regexp).join('') ); // 79035419441
```
That was a character class for digits. There are other character classes as well.
@ -54,9 +54,9 @@ For instance, `pattern:CSS\d` matches a string `match:CSS` with a digit after it
```js run
let str = "Is there CSS4?";
let reg = /CSS\d/
let regexp = /CSS\d/
alert( str.match(reg) ); // CSS4
alert( str.match(regexp) ); // CSS4
```
Also we can use many character classes:
@ -113,11 +113,11 @@ alert( "Z".match(/./) ); // Z
Or in the middle of a regexp:
```js run
let reg = /CS.4/;
let regexp = /CS.4/;
alert( "CSS4".match(reg) ); // CSS4
alert( "CS-4".match(reg) ); // CS-4
alert( "CS 4".match(reg) ); // CS 4 (space is also a character)
alert( "CSS4".match(regexp) ); // CSS4
alert( "CS-4".match(regexp) ); // CS-4
alert( "CS 4".match(regexp) ); // CS 4 (space is also a character)
```
Please note that a dot means "any character", but not the "absense of a character". There must be a character to match it: