Basic String Manipulation Features in JavaScript

Lesson Overview

Welcome! In this lesson, we'll delve into the basic string manipulation features of JavaScript, which include string tokenization, string concatenation, trimming of whitespace from strings, and type conversion operations .

Tokenizing a String in JavaScript

In JavaScript, we can use the split method from the String class to tokenize a string, essentially splitting it into smaller parts or 'tokens'. JavaScript let sentence = "JavaScript is an amazing language!"; let tokens = sentence.split(" "); tokens.forEach(token => console.log(token)); // Output: // JavaScript // is // an // amazing // language! We start by declaring a string variable sentence containing the text "JavaScript is an amazing language!". On the second line, we use the split method with a space character " " as the delimiter. This method splits the sentence every time it encounters a space and returns an array of substrings or tokens. In this case, the resulting tokens array will contain ["JavaScript", "is", "an", "amazing", "language!"]. We then use the forEach method to iterate over each element (token) in the tokens array. The arrow function token => console.log(token) is executed for each token, printing each word to the console, one per line.

Exploring String Concatenation

In JavaScript, the + operator or template literals can be used to concatenate strings into a larger string: Using the + Operator: JavaScript let str1 = "Hello,"; let str2 = " World!"; let greeting = str1 + str2; console.log(greeting); // Output: "Hello, World!" Using Template Literals: JavaScript let str1 = "Hello,"; let str2 = " World!"; let greeting = `${str1} ${str2}`; console.log(greeting); // Output: "Hello, World!" You can also concatenate arrays of strings in JavaScript using the join method: Using Array join Method: JavaScript let strings = ["Hello", " World!", " JavaScript", " Arrays!"]; let result = strings.join(""); console.log(result); // Output: "Hello World! JavaScript Arrays!" In the example above: Array Initialization: We initialize an array with several strings. Using the join Method: We use the join method to concatenate all the elements of the array into a single string. The join method can also take an optional delimiter as an argument if you need to insert characters (like commas or spaces) between the elements.

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JavaScript

let str1 = "Hello,";
let str2 = " World!";
let greeting = str1 + str2;
console.log(greeting);  // Output: "Hello, World!"

JavaScript

let str1 = "Hello,";
let str2 = " World!";
let greeting = `${str1} ${str2}`;
console.log(greeting);  // Output: "Hello, World!"

JavaScript

let strings = ["Hello", " World!", " JavaScript", " Arrays!"];
let result = strings.join("");
console.log(result);  // Output: "Hello World! JavaScript Arrays!"

JavaScript

let str = "    Hello, World!    "; // string with leading and trailing spaces
str = str.trim(); // remove leading and trailing spaces
console.log(str); // Output: "Hello, World!"

let str = "    Hello, World!    "; // string with leading and trailing spaces
str = str.trim(); // remove leading and trailing spaces
console.log(str); // Output: "Hello, World!"

JavaScript

let numStr = "123";
let num = parseInt(numStr);
console.log(num);  // Output: 123

let floatStr = "3.14";
let pi = parseFloat(floatStr);
console.log(pi);  // Output: 3.14

let age = 20;
let ageStr = String(age);
console.log("I am " + ageStr + " years old."); // Output: I am 20 years old.

let numStr = "123";
let num = parseInt(numStr);
console.log(num);  // Output: 123

let floatStr = "3.14";
let pi = parseFloat(floatStr);
console.log(pi);  // Output: 3.14

let age = 20;
let ageStr = String(age);
console.log("I am " + ageStr + " years old."); // Output: I am 20 years old.

JavaScript

let numbers = "1,2,3,4,6";
let numArray = numbers.split(",");
let sum = 0;

numArray.forEach(numStr => {
    sum += parseInt(numStr);
});

let average = sum / numArray.length;
console.log("The average is " + average);  // Output: The average is 3.2

let numbers = "1,2,3,4,6";
let numArray = numbers.split(",");
let sum = 0;

numArray.forEach(numStr => {
    sum += parseInt(numStr);
});

let average = sum / numArray.length;
console.log("The average is " + average);  // Output: The average is 3.2

JavaScript

let str = "    Hello, World!    "; // string with leading and trailing spaces
str = str.trim(); // remove leading and trailing spaces
console.log(str); // Output: "Hello, World!"

JavaScript

let numStr = "123";
let num = parseInt(numStr);
console.log(num);  // Output: 123

let floatStr = "3.14";
let pi = parseFloat(floatStr);
console.log(pi);  // Output: 3.14

let age = 20;
let ageStr = String(age);
console.log("I am " + ageStr + " years old."); // Output: I am 20 years old.

JavaScript

let numbers = "1,2,3,4,6";
let numArray = numbers.split(",");
let sum = 0;

numArray.forEach(numStr => {
    sum += parseInt(numStr);
});

let average = sum / numArray.length;
console.log("The average is " + average);  // Output: The average is 3.2

Lesson Overview

Tokenizing a String in JavaScript

Exploring String Concatenation

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Trimming Whitespace from Strings

JavaScript Type Conversions

Integrating String Tokenization and Type Conversions

Quick Recap and Next Steps