/katia/.test("Hello katia!"); //the regular expression here is katia, the string "Hello katia!" is tested if it contains katia
/katia/.test("Hello Katia!");
/katia/i.test("Hello Katia!"); // i flag outside / closing the regex is used to ignore case (caps or not)
/^(?!.*bruno).+$/.test("bruno");
/\b(?!\d+[50]0)\d+\b/.test("100");
/^[+-]?\d*\.?\d+$/.test("2..3")
/^#([a-f\d]{3}){1,2}$/i.test("#000")
/a(b|c)/.test("ac")
/^a/.test('abcd');
/a$/.test('Fahima');
/no$/.test('Bruno');
/sna$/.test('Husna');
/^Jon/.test('Jonathan');
/c.+t/.test('cymbalist');
/z*/.test('');
/1+2*3+/.test('1111223');
/1+2*3+/.test('11113');
/1+2+3+/.test('1111223');
/./.test('\n');
/.+/.test('');
/horse+/.test('horseeeeee');
/dog|cat/.test("It's raining cats and dogs.");
/dog|cat/.test("It's raining only cats.");
/dog|cat/.test("It's raining only dogs.");
/dog|cat/.test("It's raining men.");
/^a|b$/.test('ax'); // the regex here reads starts with an a or ends with a b
/^a|b$/.test('ghkjkjb'); // the regex here reads starts with an a or ends with a b
/(^a)|(b$)/.test('ax'); //brackets work like in normal JS
/^(a|b)$/.test('a');
/[a-zA-Z]+ [a-zA-Z]+!/.test("Hello Melissa!");
/^Levi/.test("Levi");
/cats|dogs/.test("It's raining cats and dogs.");
/^[a-d]/.test('abcd');
/emergency/.test('emergency');
/^a few words$/.test('a few words');
/.* horses$/.test('several horses');
/^/.test('abcd');
/\s/.test('\n');
/ct/.test('ct');
/1+2+/.test('11111222');
/\+/.test('+');
/\++/.test('++'); // \+ evaluates as a plus sign but the second plus is one or more
/.\+./.test('1+1');
/.\./.test('1+1.');
/\^/.test('^');
/\$$/.test('a$');
/\s/.test(' ');
/\s/.test('\n');
/\s/.test('');
/\d/.test('0');
/\d/.test('123');
/\d/.test('a');
/\D/.test('a');
/^\d*$/.test('3000');
/[a-c]/.test('cat');
/^[a-c]+$/.test('cat');
/^[act]+$/.test('cat');
/^[acth]+$/.test('cat');
/^[acth]+$/.test('catz');
/[eaouiy]/.test('abracadabra'); // tests if the string contains vowels
/^\d{3}-\d{4}$/.test("333-3333")
/^[\w.+-]+@[\w-]+\.[\w-.]+$/.test("bruno.silva@ada.ac.uk")
Replace method in JS
You can search and replace text in a string using .replace() on a string.
Unlike .test(), .replace() is chained to a string value.
The parameters for .replace() are:
the regex pattern you want to search for.
the string to replace the match or a function to do something.
"recognize".replace(/z/g, "s"); // the g flag finds all matches in the string
"recognizing initialization".replace(/z/g, "s");
"recognizing initialization".replace(/z/, "s"); // without the g flag only the first match is replaced
"this code removes vowels from a string".replace(/[aeouiy]/g, '');
"this code removes vowels and double spaces from a string".replace(/[aeouiy]/g, '').replace(" ", " ");
"this code replaces vowels with stars".replace(/[aeouiy]/g, char => '⭐️');
"this code Makes vOweLs lowEr casE".replace(/[aeouiy]/ig, char => char.toLowerCase());
.trim()
Sometimes whitespace characters around strings are not wanted. Typical processing of strings is to remove the whitespace at the start and at the end.
String.prototype.trim() method allows to do it easily.
" hello ".trim();
" bruno is tired ".trim();
"I love codewards".replace(/code/g, "s"); // swards - the upper layer of soil, especially when covered with grass.
"I naughtyword hate Mondays".replace(/naughtyword/g, '******')
"I'm happy this morning :3".replace(/:3/g, char => '😊');
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
