Lecture 52:-  String Operations

In Java, the String class provides a wide range of methods to perform various operations on strings. Here are some common string operations that you can perform using the String class methods:

1. Concatenation: The + operator is used for string concatenation, which combines two or more strings into a single string.

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   String firstName = "John"; String lastName = "Doe"; String fullName = firstName + " " + lastName; // fullName is "John Doe"

2. Length: The length() method returns the number of characters in a string.

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   String text = "Hello, World!"; int length = text.length(); // length is 13

3. Substring: The substring() method extracts a portion of the string based on the specified indices.

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   String text = "Hello, World!"; String substring1 = text.substring(0, 5); // substring1 is "Hello" String substring2 = text.substring(7);    // substring2 is "World!"

4. Conversion: You can convert a string to uppercase or lowercase using the toUpperCase() and toLowerCase() methods, respectively.

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   String text = "Hello, World!"; String upperCaseText = text.toUpperCase();   // upperCaseText is "HELLO, WORLD!" String lowerCaseText = text.toLowerCase();   // lowerCaseText is "hello, world!"

5. Trimming: The trim() method removes leading and trailing white spaces from a string.

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   String text = "   Hello, World!   "; String trimmedText = text.trim(); // trimmedText is "Hello, World!"

6. Replacement: The replace() method replaces occurrences of a substring with another substring.

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   String text = "Hello, World!"; String replacedText = text.replace("Hello", "Hi"); // replacedText is "Hi, World!"

7. Splitting: The split() method is used to split a string into an array of substrings based on a delimiter.

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   String text = "apple,orange,banana"; String[] fruits = text.split(","); // fruits is {"apple", "orange", "banana"}

8. Checking Contains: The contains() method checks if a particular substring is present in the string.

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   String text = "Java Programming"; boolean containsJava = text.contains("Java"); // containsJava is true boolean containsPython = text.contains("Python"); // containsPython is false

9. Formatting: You can format strings using the String.format() method or by using the + operator with placeholders.

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   String name = "John"; int age = 30; String formattedString = String.format("My name is %s and I am %d years old.", name, age); // formattedString is "My name is John and I am 30 years old."

These are just a few examples of the many string operations that you can perform using the String class methods in Java. Strings are a fundamental part of programming, and understanding how to work with strings is essential in many Java applications.