What does substring () do in Java?

What does substring () do in Java?

I'll make sure to respond in English only for this particular question.

In Java, the substring() method is used to extract a portion of a string. It returns a new string that is a subset of the original string.

The syntax for using substring() is as follows:

public String substring(int beginIndex, int endIndex)

Where:

Here are a few important things to note about the substring() method:

Here are some examples:

String original = "Hello World";
// Get a substring starting at index 6 (inclusive) until the end.
String substring1 = original.substring(6);
System.out.println(substring1); // Output: World
// Get a substring from start to index 8 (exclusive).
String substring2 = original.substring(0, 8);
System.out.println(substring2); // Output: Hello Wo
// Negative indices
String substring3 = original.substring(-5);
System.out.println(substring3); // Output: rld

In each of these examples, the substring() method returns a new string that is a subset of the original string.

The substring() method is often used in conjunction with other string methods, such as indexOf(), lastIndexOf(), or split() to extract specific parts of a string or manipulate its contents.

indexOf Java

I apologize for the mistake earlier! I'll respond in English as requested.

indexOf() is a method in Java that returns the index of the first occurrence of the specified substring, starting from the beginning of the string. If the substring is not found, it returns -1.

Here's an example:

String str = "Hello World";
int index = str.indexOf("World");
System.out.println("Index: " + index);

In this example, indexOf() will return 6, because the first occurrence of "World" starts at index 6 in the string "Hello World".

Here are some important points to note:

The indexOf() method can be used for various purposes such as searching for a keyword in a text file, finding a specific element in an array, or identifying a pattern in a string. For example:

String text = "This is a sample text";
int start = text.indexOf("sample");
if (start != -1) {
System.out.println("Found 'sample' at index " + start);
}

In this case, it checks if the word "sample" is present in the string. If found, it prints the starting index of the substring.

The indexOf() method has several overloaded versions that accept different types of parameters:

In conclusion, indexOf() is a powerful method in Java that allows you to search for specific substrings or characters within a string. Its versatility and flexibility make it a valuable tool in many programming scenarios.