Get element in string java

How to Find an Element in a String using Java Programming Language

Learn different methods to find an element in a string using Java programming language. Explore key points, important points, and helpful points related to the topic.

• Using indexOf() method
• Using lastIndexOf() method
• Using charAt() method
• Using contains() method
• Searching for an element in a string array
• Using strchr() function
• Other helpful code examples for finding an element in a string using Java programming language
• Conclusion
• How to get element from string in Java?
• How to find characters in a string in Java?
• How to search for an element in a string array in Java?
• How do I find a character in a string?

String manipulation is a crucial aspect of programming, and it is a task that programmers encounter often. In Java programming language , there are several methods available to search for an element in a string. In this blog post, we will explore different methods to find an element in a string using Java programming language. We will discuss key points, important points, and helpful points related to the topic.

Using indexOf() method

The indexOf() method is one of the most commonly used methods to search for an element in a string in Java. The method returns the position of the first occurrence of the specified character(s) in a string. The syntax of the indexOf() method is as follows:

int indexOf(int ch); int indexOf(String str); 

Here, the first syntax returns the index of the first occurrence of the specified character, and the second syntax returns the index of the first occurrence of the specified string. Here’s an example:

String str = "Hello world"; int index = str.indexOf('o'); // index = 4 

In the example above, we have a string str that contains the value “Hello world.” We then use the indexOf() method to search for the first occurrence of the character ’o’ in the string. The indexOf() method returns the index of the first occurrence of the character ’o,’ which is 4.

Using lastIndexOf() method

The lastIndexOf() method is similar to the indexOf() method, but it returns the position of the last occurrence of the specified character(s) in a string. The syntax of the lastIndexOf() method is as follows:

int lastIndexOf(int ch); int lastIndexOf(String str); 

Here, the first syntax returns the index of the last occurrence of the specified character, and the second syntax returns the index of the last occurrence of the specified string. Here’s an example:

String str = "Hello world"; int index = str.lastIndexOf('o'); // index = 7 

In the example above, we have a string str that contains the value “Hello world.” We then use the lastIndexOf() method to search for the last occurrence of the character ’o’ in the string. The lastIndexOf() method returns the index of the last occurrence of the character ’o,’ which is 7.

Using charAt() method

The charAt() method returns the character at the specified index in a string. We can use the charAt() method to search for a specific character in a string. The syntax of the charAt() method is as follows:

Here, the charAt() method takes an integer index as input and returns the character at that index. Here’s an example:

String str = "Hello world"; char ch = str.charAt(4); // ch = 'o' 

In the example above, we have a string str that contains the value “Hello world.” We then use the charAt() method to get the character at the index 4 in the string. The charAt() method returns the character ’o,’ which is at index 4.

Using contains() method

The contains() method checks whether the specific set of characters are part of the given string or not. We can use the contains() method to search for a specific set of characters in a string. The syntax of the contains() method is as follows:

boolean contains(CharSequence sequence); 

Here, the contains() method takes a CharSequence as input and returns true if the sequence is present in the string and false otherwise. Here’s an example:

String str = "Hello world"; boolean contains = str.contains("world"); // contains = true 

In the example above, we have a string str that contains the value “Hello world.” We then use the contains() method to check if the string “world” is present in the string. The contains() method returns true since the string “world” is present in the string.

Searching for an element in a string array

To search for an element in a string array, we can use a for loop to iterate through the array and compare each element with the search element. Here’s an example:

String[] arr = "apple", "banana", "orange">; String search = "banana"; for (String s : arr)  if (s.equals(search))  System.out.println("Found!"); > > 

In the example above, we have a string array arr that contains the values “apple,” “banana,” and “orange.” We then define a search element search as “banana.” We use a for loop to iterate through each element in the array and compare it with the search element. If the element matches the search element, we print “Found!” to the console.

Using strchr() function

The strchr() function is a C function that can be used to find the first occurrence of a character in a string. We can use this function in Java by calling a native C library using the Java Native Interface (JNI). Here’s an example:

public class Strchr  static  System.loadLibrary("strchr"); > public static native String strchr(String str, int c); public static void main(String[] args)  String str = "Hello world"; String ch = strchr(str, 'o'); // ch = "orld" > > 

In the example above, we have a class Strchr that defines a native method strchr() that calls the strchr() function from a C library. We then load the library using the System.loadLibrary() method. Finally, we call the strchr() method to search for the first occurrence of the character ’o’ in the string “Hello world.” The strchr() method returns the string “orld,” which is the substring after the first occurrence of the character ’o.’

Other helpful code examples for finding an element in a string using Java programming language

In java, java string find code example

String str = "Hello world!"; int worldIndex = str.indexOf("world")); // found: worldIndex = 6 int moonIndex = str.indexOf("moon")); // not found: moonIndex == -1if (str.indexOf("world")) != -1)

Conclusion

In conclusion, Java provides several methods to search for elements in a string, such as indexOf() , lastIndexOf() , charAt() , contains() . To search for an element in a string array, use a for loop to iterate through the array. The strchr() function can be used to find the first occurrence of a character in a string. By using these methods, you can easily search for an element in a string using Java programming language.

Источник

Get element in string java

• Searching For Characters and Substring in a String in Java
• Program to reverse a string (Iterative and Recursive)
• Left Rotation and Right Rotation of a String
• Sort string of characters
• Print the frequency of each character in Alphabetical order
• Swap characters in a String
• C program to find the length of a string
• How to insert characters in a string at a certain position?
• Program to check if two strings are same or not
• Concatenating Two Strings in C
• Remove all occurrences of a character in a string

• Program to print all substrings of a given string
• Print all subsequences of a string
• Count Distinct Subsequences
• Count distinct occurrences as a subsequence
• Longest Common Subsequence (LCS)
• Shortest Superstring Problem
• Printing Shortest Common Supersequence
• Shortest Common Supersequence
• Longest Repeating Subsequence
• Longest Palindromic Subsequence (LPS)
• Longest Palindromic Substring

• K’th Non-repeating Character
• Queries for characters in a repeated string
• URLify a given string (Replace spaces with %20)
• Count of total anagram substrings
• Count number of binary strings without consecutive 1’s
• Lexicographically next string
• Check if given string can be split into four distinct strings
• Word Break Problem | (Trie solution)
• Check for balanced parentheses in an expression | O(1) space
• Length of Longest Balanced Subsequence
• Minimum Swaps for Bracket Balancing
• Convert a sentence into its equivalent mobile numeric keypad sequence
• Burrows – Wheeler Data Transform Algorithm
• Form minimum number from given sequence
• Print shortest path to print a string on screen
• Mirror characters of a string

• Multiply Large Numbers represented as Strings
• Count ways to increase LCS length of two strings by one
• Minimum rotations required to get the same string
• Find if an array of strings can be chained to form a circle | Set 2
• Given a sorted dictionary of an alien language, find order of characters
• Remove minimum number of characters so that two strings become anagram
• Minimum Number of Manipulations required to make two Strings Anagram Without Deletion of Character
• Palindrome Substring Queries
• Minimum Word Break
• Minimum number of bracket reversals needed to make an expression balanced
• Word Wrap problem ( Space optimized solution )
• Decode a string recursively encoded as count followed by substring

• Searching For Characters and Substring in a String in Java
• Program to reverse a string (Iterative and Recursive)
• Left Rotation and Right Rotation of a String
• Sort string of characters
• Print the frequency of each character in Alphabetical order
• Swap characters in a String
• C program to find the length of a string
• How to insert characters in a string at a certain position?
• Program to check if two strings are same or not
• Concatenating Two Strings in C
• Remove all occurrences of a character in a string

• Program to print all substrings of a given string
• Print all subsequences of a string
• Count Distinct Subsequences
• Count distinct occurrences as a subsequence
• Longest Common Subsequence (LCS)
• Shortest Superstring Problem
• Printing Shortest Common Supersequence
• Shortest Common Supersequence
• Longest Repeating Subsequence
• Longest Palindromic Subsequence (LPS)
• Longest Palindromic Substring

• K’th Non-repeating Character
• Queries for characters in a repeated string
• URLify a given string (Replace spaces with %20)
• Count of total anagram substrings
• Count number of binary strings without consecutive 1’s
• Lexicographically next string
• Check if given string can be split into four distinct strings
• Word Break Problem | (Trie solution)
• Check for balanced parentheses in an expression | O(1) space
• Length of Longest Balanced Subsequence
• Minimum Swaps for Bracket Balancing
• Convert a sentence into its equivalent mobile numeric keypad sequence
• Burrows – Wheeler Data Transform Algorithm
• Form minimum number from given sequence
• Print shortest path to print a string on screen
• Mirror characters of a string

• Multiply Large Numbers represented as Strings
• Count ways to increase LCS length of two strings by one
• Minimum rotations required to get the same string
• Find if an array of strings can be chained to form a circle | Set 2
• Given a sorted dictionary of an alien language, find order of characters
• Remove minimum number of characters so that two strings become anagram
• Minimum Number of Manipulations required to make two Strings Anagram Without Deletion of Character
• Palindrome Substring Queries
• Minimum Word Break
• Minimum number of bracket reversals needed to make an expression balanced
• Word Wrap problem ( Space optimized solution )
• Decode a string recursively encoded as count followed by substring

Источник