Regular expressions, often shortened to "regex" or "regexp", are patterns that help programmers match, search, and replace text. And in my dev journey I never feel like I need to learn regex, because it seemed so difficult to learn.But on my ride to complete the freeCodeCamp course i need to take this regex lessons on freeCodeCamp.
My daily code
I have done 13 of the 33 exercise, i have learned the basics of regex and find some ressources to test and getting more info on how to use it .
What did i learn ?
The basic format of a regex is like this :
/ expression / flags, i.e /[A-Z]+/g
You can group your expression by using parentheses (), or you can combine them by using logical OR |, it's possible to affect the search by using flags
In javascript you have multiple ways to use regex the first one is .test()
let testStr = "freeCodeCamp";
let testRegex = /Code/;
testRegex.test(testStr); // true
The second way is to find a matching string with
.match()
const paragraph = 'The quick brown fox jumps over the lazy dog. It barked.';
const regex = /[A-Z]/g;
const found = paragraph.match(regex); //Array ["T", "I"]
Common Regex symbol or flag
| Symbol | Meaning |
|---|---|
| i flag | the search is case-insensitive |
| g flag | the search looks for all matches |
| * | Match 0 or more characters |
| + | Match 1 or more characters |
| [abc] | Any of a,b or c |
| [^abc] | not a,b or c |
| [a-z] | Any letter from a to z |
| [a-c2-8] | Any letter or number from a to z or from 2 to 8 |
Usefull Ressources
- regexr
- regex101 really similar to regexr
- MDN Docs
- Regular Expressions (RegEx) in 100 Seconds and there cheatsheet
- iHateRegex you can find a article on dev.to about it
Thank you for reading this post, hope you loved it 😀
PS:
- if you see any spelling or grammar mistakes, can you notify me (I am still improving my English) ? thank you !
- if you have any tips for improving my post feel free to comment on the post
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