String Operations

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.

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