String Methods 🚀🚀

Before delving into string methods, it's crucial to understand a fundamental aspect of strings: they are immutable. Now, you might be wondering what I mean by 'immutable,' so let me explain 🙂

strings are immutable. Now you guys were thinking about what I mean by immutable, so let me explain this.

Strings are Immutable 🚀

strings are immutable. This means that once a string is created, its value cannot be changed. Any operation that appears to modify a string actually creates a new string with the modified value.

let str = "Hello, World!";

// Attempt to modify the string
// This doesn't change the original string, it creates a new one

// string.replace(searchValue, replaceValue);
let modifiedStr = str.replace("Hello", "Hi");

console.log(str);          // Output: Hello, World!
console.log(modifiedStr);  // Output: Hi, World!

the replace method is used to replace a specified substring or pattern in a string with another substring.

In this example, the replace method doesn't change the value of the original str variable. Instead, it creates a new string (modifiedstr) with the modified value. The original string remains unchanged.

String Methods🚀

1. trim() method:- In JavaScript, the trim method is used to remove the leading and trailing whitespace from a string.

    let s = "      Hello, World!      ";
    let trimmedS = s.trim();
    console.log(trimmedS);  // Output: Hello, World!
   

   As strings are immutable, it does not change the actual string, the trim method returns a new string (trimmed string).

2. toUpperCase() method:- The toUpperCase method is used to convert all the characters in a string to uppercase.

    let str = "Hello, World!";
    let upperCaseStr = str.toUpperCase();
   
    console.log(upperCaseStr);  // Output: HELLO, WORLD!
   

   the toUpperCase method is called on the str variable, which contains the string "Hello, World!". toUpperCase method does not modify the original string; it returns a new string with the changes.

3. toLowerCase():- The toLowerCase method is used to convert all the characters in a string to lowercase.

    let str = "Hello, World!";
    let lowerCaseStr = str.toLowerCase();
   
    console.log(lowerCaseStr);  // Output: hello, world!
   

   Similar to toUpperCase, the toLowerCase method does not modify the original string; it returns a new string with all characters converted to lowercase.

   If you want to modify the original string, you would need to assign the result back to the variable.

    let str = "Hello, World!";
    str = str.toLowerCase();
   
    console.log(str);  // Output: hello, world!
   

   This way, the original string str is updated with its lowercase version.

4. slice() method:- The slice method is used to extract a portion of a string and create a new string without modifying the original one. Here is the syntax-

    string.slice(startIndex, endIndex+1);
   

• startIndex: The index at which to begin extraction. If negative, it is treated as counting from the end of the string.

• endIndex: The index at which to end extraction.

let str = "Hello, World!";

// Example 1: Extract from index 0 to 4 (so we will take 4+1 index, 
//so that 5th index character will include )

let slicedStr1 = str.slice(0, 5);
console.log(slicedStr1);  // Output: Hello

// Example 2: Extract from index 7 to the end.
let slicedStr2 = str.slice(7);  // ignored the endIndex here, 
//so the endIndex goes to the end. 
console.log(slicedStr2);  // Output: World!

// Example 3: Extract the last 6 characters
let slicedStr3 = str.slice(-6);
console.log(slicedStr3);  // Output: World!

// Example 4: Extract from index -5 to -1 (not including -1)
let slicedStr4 = str.slice(-5, -1);
console.log(slicedStr4);  // Output: orld

//Example 5: Extract from starting to the end .
let slicedStr5 = str.slice(,);

In these examples, the slice method is used to extract substrings from the original string str based on the specified indices. Remember that slice does not modify the original string; it returns a new string with the extracted portion.

👉In the next episode, we will discuss template strings and string concatenation. I hope you are as excited as I am about delivering the upcoming episodes.

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