What is indexOf () in Java?

The indexOf() method returns the position of the first occurrence of specified character(s) in a string. Tip: Use the lastIndexOf method to return the position of the last occurrence of specified character(s) in a string.

How do you return indices in Java?

Java String indexOf() Method Example

public class IndexOfExample{
public static void main(String args[]){
String s1=”this is index of example”;
//passing substring.
int index1=s1.indexOf(“is”);//returns the index of is substring.
int index2=s1.indexOf(“index”);//returns the index of index substring.

What does indexOf do?

indexOf() The indexOf() method, given one argument: a substring to search for, searches the entire calling string, and returns the index of the first occurrence of the specified substring.

Can you index a string in Java?

You can get the character at a particular index within a string by invoking the charAt() accessor method. The index of the first character is 0, while the index of the last character is length()-1 . For example, the following code gets the character at index 9 in a string: String anotherPalindrome = “Niagara.

What is the difference between indexOf () and charAt () methods?

Expert-verified answer

The char At () method of the string class returns the char value at the specified index. The index Of () method is used to get the integer value of a particular index of String type object.

Does indexOf return?

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

How do I return two indexes in an array in Java?

We can use following solutions to return multiple values.

If all returned elements are of same type.
If returned elements are of different types.
Using Pair (If there are only two returned values) We can use Pair in Java to return two values.
If there are more than two returned values.
Returning list of Object Class.

How do I return an index from an array?

To find the position of an element in an array, you use the indexOf() method. This method returns the index of the first occurrence the element that you want to find, or -1 if the element is not found.

Can index be used on strings?

Strings are ordered sequences of character data, 00:15 and the individual characters of a string can be accessed directly using that numerical index. String indexing in Python is zero-based, so the very first character in the string would have an index of 0 , 00:30 and the next would be 1 , and so on.

How do you find a letter in a string?

You can search for a particular letter in a string using the indexOf() method of the String class. This method which returns a position index of a word within the string if found. Otherwise it returns -1.

What does indexOf return if not found?

The indexOf() method returns the position of the first occurrence of a value in a string. The indexOf() method returns -1 if the value is not found.

What are the differences between indexOf () and lastIndexOf ()?

The indexOf() and lastIndexOf() function return a numeric index that indicates the starting position of a given substring in the specified metadata string: indexOf() returns the index for the first occurrence of the substring. lastIndexOf() returns the index for the last occurrence of the substring.

What does it mean indexOf (- 1?

indexOf() The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

What is the meaning of indexOf >- 1?

no match found
-1 means “no match found”. The reason it returns -1 instead of “false” is that a needle at the beginning of the string would be at position 0, which is equivalent to false in Javascript.

Can you return 2 values in Java?

You can return only one value in Java. If needed you can return multiple values using array or an object.

How can I return two data types in Java?

5 ways to return multiple values from a method in Java

Using a POJO class instance. This is the most commonly used method to return multiple values from a method in Java.
Using javafx. util.
Return an array of specific type or an object array.
Return a Collection.

How do I find the index of an object?

To find the index of an object in an array, by a specific property: Use the map() method to iterate over the array, returning only the value of the relevant property. Call the indexOf() method on the returned from map array. The indexOf method returns the index of the first occurrence of a value in an array.

How do string indexes work?

String indexing in Python is zero-based, so the very first character in the string would have an index of 0 , 00:30 and the next would be 1 , and so on. The index of the last character will be the length of the string minus one.

Can an array index be a string?

Actually, it has very much to do with the question (specifically, yes, you CAN use a string as an index, but not in the obvious way that the original querier wants).

How do I find a word in a string in Java?

To find a word in the string, we are using indexOf() and contains() methods of String class. The indexOf() method is used to find an index of the specified substring in the present string. It returns a positive integer as an index if substring found else returns -1.

How do I extract a letter from a string in Java?

Using String. getChars() method:

Get the string and the index.
Create an empty char array of size 1.
Copy the element at specific index from String into the char[] using String. getChars() method.
Get the specific character at the index 0 of the character array.
Return the specific character.

Does indexOf return null?

indexOf will never return null when run on an array; one of your preceding variables ( backendInfo or one of its properties) must be the culprit.

How do I use lastIndexOf?

Definition and Usage
The lastIndexOf() method searches the string from the end to the beginning. The lastIndexOf() method returns the index from the beginning (position 0). The lastIndexOf() method returns -1 if the value is not found. The lastIndexOf() method is case sensitive.

What does lastIndexOf return?

The lastIndexOf() method returns the last index at which a given element can be found in the array, or -1 if it is not present. The array is searched backwards, starting at fromIndex .

What does it mean when indexOf returns 0?

If value consists only of one or more ignorable characters, the IndexOf(String) method always returns 0 (zero) to indicate that the match is found at the beginning of the current instance.

How do you write indexOf in Java?

Java String indexOf(int char, int fromIndex) Method Example

public class IndexOfExample4 {
public static void main(String[] args) {
String s1 = “This is indexOf method”;
// Passing char and index from.
int index = s1.indexOf(‘e’, 12); //Returns the index of this char.
System.out.println(“index of char “+index);
}
}

What indexOf () will do?

How do you substring in Java?

Java String substring() Method Example 2

public class SubstringExample2 {
public static void main(String[] args) {
String s1=”Javatpoint”;
String substr = s1.substring(0); // Starts with 0 and goes to end.
System.out.println(substr);
String substr2 = s1.substring(5,10); // Starts from 5 and goes to 10.

The char At () method of the string class returns the char value at the specified index. The index Of () method is used to get the integer value of a particular index of String type object.

How do you compare two strings in Java?

Using String. equals() :In Java, string equals() method compares the two given strings based on the data/content of the string. If all the contents of both the strings are same then it returns true. If any character does not match, then it returns false.

Which method is used to search for a substring?

The String class provides two accessor methods that return the position within the string of a specific character or substring: indexOf and lastIndexOf . The indexOf method searches forward from the beginning of the string, and lastIndexOf searches backward from the end of the string.

How does substring () inside string works?

The substring(int beginIndex, int endIndex) method of the String class. It returns a new string that is a substring of this string. The substring begins at the specified beginIndex and extends to the character at index endIndex – 1. Thus the length of the substring is endIndex-beginIndex.

How do I use substring?

The substr() method extracts a part of a string. The substr() method begins at a specified position, and returns a specified number of characters. The substr() method does not change the original string. To extract characters from the end of the string, use a negative start position.

Can we use == to compare strings in Java?

You should not use == (equality operator) to compare these strings because they compare the reference of the string, i.e. whether they are the same object or not. On the other hand, equals() method compares whether the value of the strings is equal, and not the object itself.

What is difference between == equals () and compareTo () method?

equals() checks if two objects are the same or not and returns a boolean. compareTo() (from interface Comparable) returns an integer. It checks which of the two objects is “less than”, “equal to” or “greater than” the other.

How do substring () and substr () differ?

The difference between substring() and substr()
The two parameters of substr() are start and length , while for substring() , they are start and end . substr() ‘s start index will wrap to the end of the string if it is negative, while substring() will clamp it to 0 .

How do I find all the substrings of a string?

JAVA

public class AllSubsets {
public static void main(String[] args) {
String str = “ABC”;
int len = str.length();
int temp = 0;
//Total possible subsets for string of size n is n*(n+1)/2.
String arr[] = new String[len*(len+1)/2];
//This loop maintains the starting character.

How do I get a substring?

The substring() method extracts characters, between two indices (positions), from a string, and returns the substring. The substring() method extracts characters from start to end (exclusive). The substring() method does not change the original string.

What is substr () Instr () functions?

The substr functions allows you to extract a substring from a string. The instr function returns the location of a substring in a string.

How do you find the index of a substring?

The string index() method returns the lowest index of a substring in a string. The index() method has three parameters: sub is the substring to search for in the str . start and end parameters are interpreted as in the slice notation str[start:end] .

Can you index strings?

Because strings, like lists and tuples, are a sequence-based data type, it can be accessed through indexing and slicing.

How do I compare two strings in Java?

Can you use == for strings in Java?

To compare these strings in Java, we need to use the equals() method of the string. You should not use == (equality operator) to compare these strings because they compare the reference of the string, i.e. whether they are the same object or not.

What does === mean in Java?

On the other hand === is known as strictly equality operator. It’s much similar Java’s equality operator (==), which gives compilation error if you compare two variables, whose types are not compatible to each other. In fact, you should always use “===” operator for comparing variables or just for any comparison.

Should I use substr or substring?

substr() ‘s start index will wrap to the end of the string if it is negative, while substring() will clamp it to 0 . Negative lengths in substr() are treated as zero, while substring() will swap the two indexes if end is less than start .

What is indexOf () in Java?