In this section, we'll explore the fundamental string operations that form the core of string manipulation. These operations are widely used in programming tasks and coding interviews.

Concatenation: How to combine strings.

Concatenation refers to the operation of joining two or more strings end-to-end. It's a fundamental technique in text processing, allowing you to create new strings by combining existing ones.

1// JavaScript
2var str1 = "Hello, ";
3var str2 = "World!";
4var result = str1.concat(str2); // "Hello, World!"

Substring Extraction: How to extract parts of a string.

Extracting substrings involves taking a portion of a string, defined by a starting and ending position. This is useful when you need to isolate specific parts of a text, such as parsing user input or processing a file.

1// JavaScript
2var str = "Hello, World!";
3var result = str.substring(7, 12); // "World"

String Length: Finding the length of a string.

The length of a string refers to the number of characters it contains. Understanding the length is essential for tasks like looping through characters, validating input, or allocating memory.

1// JavaScript
2var str = "Hello, World!";
3var length = str.length; // 13

String Comparison: Comparing strings for equality and ordering.

Comparing strings allows you to determine if two strings are equal or if one comes before or after the other in a given order (such as alphabetical). This is vital for sorting, searching, and validating data.

1// JavaScript
2var str1 = "apple";
3var str2 = "orange";
4var isEqual = str1 === str2; // false
5var isOrdered = str1 < str2; // true

Case Conversion: Changing the case of characters within a string.

Case conversion involves changing the case of characters within a string, either to upper or lower case. This is useful for case-insensitive comparisons, text normalization, and user-friendly display.

1// JavaScript
2var str = "Hello, World!";
3var upper = str.toUpperCase(); // "HELLO, WORLD!"
4var lower = str.toLowerCase(); // "hello, world!"

Trimming and Padding: Removing leading/trailing spaces and adding padding.

Trimming refers to the removal of leading or trailing whitespace characters from a string. Padding, on the other hand, involves adding extra characters (such as spaces or zeros) to a string to reach a specific length. These operations are helpful for aligning text, formatting output, and cleaning up user input.

1// JavaScript
2var str = "   Hello, World!   ";
3var trimmed = str.trim(); // "Hello, World!"
4var padded = str.padStart(20, '0'); // "0000Hello, World!   "

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console.log(concatResult, substrResult, length, isEqual, isOrdered, upper, lower, trimmed, padded);

// JavaScript

// Concatenation

var str1 = "Hello, ";

var str2 = "World!";

var concatResult = str1.concat(str2);

​

// Substring Extraction

var str = "Hello, World!";

var substrResult = str.substring(7, 12);

​

// String Length

var length = str.length;

​

// String Comparison

var compareStr1 = "apple";

var compareStr2 = "orange";

var isEqual = compareStr1 === compareStr2;

var isOrdered = compareStr1 < compareStr2;

​

// Case Conversion

var upper = str.toUpperCase();

var lower = str.toLowerCase();

​

// Trimming and Padding

var trimStr = "   Hello, World!   ";

var trimmed = trimStr.trim();

var padded = trimStr.padStart(20, '0');

​

// Results