411 REFERENCE · Wikibooks
JavaScript/Regular expressions/Exercises
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Topic: Regular Expressions
1. Does the password "kw8h_rt" contain a digit?
100% "use strict";
const myVar = "kw8h_rt";
if (myVar.match(/\d/)) {
alert("Password is ok.");
} else {
alert("Your password does not contain a digit.");
}
2. Be creative! Define a rule for passwords, read a password from the user using prompt, and check it.
100% "use strict";
// for example:
const pw = prompt("Please enter your password (must contain two characters which are NOT alphanumeric).");
if (pw.match(/\W.*\W/)) {
alert("Your password is ok.");
} else {
alert("Your password does not conform to the rules.");
}
3. Does the sentence "Kim and Maren are friends." contains the word "are"?
100% "use strict";
const myVar = "Kim and Maren are friends.";
alert(myVar.match(/are/)); // looks good, but:
// consider word boundaries
alert(myVar.match(/\bare\b/));
// ... proof:
alert(myVar.match(/are.*/));
4. Be creative! Read strings from the user (prompt) that match the following regular expressions:
d\dd
d\d+d
\bwhy\b
x\s-\sy\s=\sz
Discuss the meaning of the above REs with your colleague.
100% "use strict";
// for example:
const myVar = prompt("What string conforms to the RE /d\dd/?");
if (myVar.match(/d\dd/)) {
alert("Bingo.");
} else {
alert("Sorry.");
}
5. Normalize the phone number "0800 123-456-0" by stripping out all non-numerical characters.
100% "use strict";
const myVar = "0800 123-456-0";
const result = myVar.replace(/\D/g, "");
alert(result);
6. Split the following sentences into an array that contains only its words.
"Tom cried: 'What the hell is going on?'. Then he left the room."
100% "use strict";
const sentence = "Tom cried: 'What the hell is going on?'. Then he left the room."
const arr = sentence.split(/\W+/); // one or more non-alphanumeric characters
alert(arr);