Regex Cheat Sheet in JavaScript - part-2
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This document is a regex cheatsheet focusing on extraction and matching techniques. It covers how to extract first matches, all matches using flags, and matches with character classes and ranges. Additionally, it explains how to use negated character sets for matching undesired characters.
![CHEAT SHEET
Extracting first match:
Using the match() function
const match = "Hello World!".match(/hello/i);
// "Hello"
Extracting all matches:
Using the g flag
const testString = "Repeat repeat rePeAT";
const regexWithAllMatches = /Repeat/gi;
testString.match(regexWithAllMatches);
// ["Repeat", "repeat", "rePeAT"]](https://image.slidesharecdn.com/hbdjt8qbrcoyliliqa1w-signature-d8f0bf69a70f15013025b23ec3f23e2888efc8299c5db35a954b0f818948bc03-poli-200609033748/85/Regex-Cheat-Sheet-in-JavaScript-part-2-2-320.jpg)
![Matching single character with multiple
possibilities:
// Match "cat" "fat" and "mat" but not "bat"
const regexWithCharClass = /[cfm]at/g;
const testString = "cat fat bat mat";
const allMatchingWords =
testString.match(regexWithCharClass);
// ["cat", "fat", "mat"]
Match a single, unknown character:
● To match a set of characters you don't want to
have, use the negated character set
● To negate a character set, use a caret ^
const allCharsNotVowels = /[^aeiou]/gi;
const allCharsNotVowelsOrNumbers =
/[^aeiou0-9]/gi;](https://image.slidesharecdn.com/hbdjt8qbrcoyliliqa1w-signature-d8f0bf69a70f15013025b23ec3f23e2888efc8299c5db35a954b0f818948bc03-poli-200609033748/85/Regex-Cheat-Sheet-in-JavaScript-part-2-3-320.jpg)
![const regexWithCharRange = /[a-e]at/;
const catString = "cat";
const batString = "bat";
const fatString = "fat";
regexWithCharRange.test(catString); // true
regexWithCharRange.test(batString); // true
regexWithCharRange.test(fatString); // false
Match letter of the alphabet:
Using range within the character range [a-z]](https://image.slidesharecdn.com/hbdjt8qbrcoyliliqa1w-signature-d8f0bf69a70f15013025b23ec3f23e2888efc8299c5db35a954b0f818948bc03-poli-200609033748/85/Regex-Cheat-Sheet-in-JavaScript-part-2-4-320.jpg)
Regex Cheat Sheet in JavaScript - part-2
- 2. CHEAT SHEET Extracting first match: Using the match() function const match = "Hello World!".match(/hello/i); // "Hello" Extracting all matches: Using the g flag const testString = "Repeat repeat rePeAT"; const regexWithAllMatches = /Repeat/gi; testString.match(regexWithAllMatches); // ["Repeat", "repeat", "rePeAT"]
- 3. Matching single character with multiple possibilities: // Match "cat" "fat" and "mat" but not "bat" const regexWithCharClass = /[cfm]at/g; const testString = "cat fat bat mat"; const allMatchingWords = testString.match(regexWithCharClass); // ["cat", "fat", "mat"] Match a single, unknown character: ● To match a set of characters you don't want to have, use the negated character set ● To negate a character set, use a caret ^ const allCharsNotVowels = /[^aeiou]/gi; const allCharsNotVowelsOrNumbers = /[^aeiou0-9]/gi;
- 4. const regexWithCharRange = /[a-e]at/; const catString = "cat"; const batString = "bat"; const fatString = "fat"; regexWithCharRange.test(catString); // true regexWithCharRange.test(batString); // true regexWithCharRange.test(fatString); // false Match letter of the alphabet: Using range within the character range [a-z]