java string search - Brave Search

Substring search in Java

stackoverflow.com › questions › 1987673 › substring-search-in-java

I'm assuming the problems you're having with indexOf() related to you using the character version (otherwise why would you be searching for w when looking for world?). If so, indexOf() can take a string argument to search for:

String s = "hello world i am from heaven";
if (s.indexOf("world") != -1) {
  // it contains world
}

as for log base 2, that's easy:

public static double log2(double d) {
  return Math.log(d) / Math.log(2.0d);
}

Answer from cletus on Stack Overflow

geeksforgeeks.org › java › searching-for-characters-and-substring-in-a-string-in-java

Searching For Characters and Substring in a String in Java - GeeksforGeeks

July 23, 2025 - The indexOf() searchesfor the first occurrence of a character from the beginning of the string and returns its index. If the character is not found, it returns -1. Note: If the given string contains multiple occurrences of a specified character ...

stackoverflow.com › questions › 1987673 › substring-search-in-java

string - Substring search in Java - Stack Overflow

I'm assuming the problems you're having with indexOf() related to you using the character version (otherwise why would you be searching for w when looking for world?). If so, indexOf() can take a string argument to search for:

String s = "hello world i am from heaven";
if (s.indexOf("world") != -1) {
  // it contains world
}

as for log base 2, that's easy:

public static double log2(double d) {
  return Math.log(d) / Math.log(2.0d);
}

For an exact String comparison, you can simply do:

boolean match = stringA.equals(stringB);

If you want to check that a string contains a substring, you can do:

boolean contains = string.contains(substring);

For more String methods, see the javadocs

regex - Extract substring in Java

java - Finding Substring from a String

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w3schools.com › java › ref_string_indexof.asp

Java String indexOf() Method

Java Examples Java Videos Java Compiler Java Exercises Java Quiz Java Code Challenges Java Practice Problems Java Server Java Syllabus Java Study Plan Java Interview Q&A · ❮ String Methods · Search a string for the first occurrence of "planet": String myStr = "Hello planet earth, you are a great planet."; System.out.println(myStr.indexOf("planet")); Try it Yourself » ·

tutorialspoint.com › javaexamples › string_search.htm

How to Search a Word inside a String in Java

This example shows how we can search a word within a String object using indexOf() method which returns a position index of a word within the string if found.

javaguides.net › 2018 › 08 › string-searching-methods-with-examples.html

String Searching Methods in Java

June 15, 2024 - The matches() method allows you to check if a string matches a given regular expression. Understanding these methods will help you manipulate and analyze strings more effectively in Java.

geeksforgeeks.org › searching-for-character-and-substring-in-a-string

Searching characters and substring in a String in Java - GeeksforGeeks

December 11, 2018 - contains(CharSequence seq): It returns true if the String contains the specified sequence of char values otherwise returns false. Its parameters specify sequence of character to be searched and throws NullPointer exception if seq is null.

javarevisited.blogspot.com › 2016 › 10 › how-to-check-if-string-contains-another-substring-in-java-indexof-example.html

How to check if String contains another SubString in Java? contains() and indexOf() example

June 26, 2025 - YES Doing search with different case isPresent: false Checking if one String contains another String using contains() in Java input string: C++ is the predecessor of Java search string: Java does substring is found inside String?

baeldung.com › home › java › java list › searching for a string in an arraylist

Searching for a String in an ArrayList | Baeldung

April 4, 2025 - public List<String> findUsingLoop(String search, List<String> list) { List<String> matches = new ArrayList<String>(); for(String str: list) { if (str.contains(search)) { matches.add(str); } } return matches; } The Java 8 Streams API provides us with a more compact solution by using functional operations.

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stackoverflow.com › questions › 9276040 › how-to-search-a-string-in-another-string

java - How to search a string in another string? - Stack Overflow

That is already in the String class:

String word = "cat";
String text = "The cat is on the table";
Boolean found;

found = text.contains(word);

Use the String.indexOf(String str) method.

From the JavaDoc:

Returns the index within this string of the first occurrence of the specified substring.

...

Returns: if the string argument occurs as a substring within this object, then the index of the first character of the first such substring is returned; if it does not occur as a substring, -1 is returned.

So:

boolean findInString(word, text)
{
  return text.indexOf(word) > -1;
}

labex.io › tutorials › java-how-to-find-a-word-in-a-java-string-using-the-indexof-method-414025

How to find a word in a Java String using the indexOf() method | LabEx

Try running the program again with different search words to see how it performs with various inputs. In this tutorial, you have learned how to use the indexOf() method in Java to find words within strings.

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StringSearchAlgorithms - Efficient String Search Algorithms in Java

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String (Java Platform SE 8 )

July 21, 2026 - The class String includes methods for examining individual characters of the sequence, for comparing strings, for searching strings, for extracting substrings, and for creating a copy of a string with all characters translated to uppercase or to lowercase. Case mapping is based on the Unicode Standard version specified by the Character class. The Java language provides special support for the string concatenation operator ( + ), and for conversion of other objects to strings.

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String Search Algorithms for Large Texts with Java

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iitk.ac.in › esc101 › 05Aug › tutorial › java › data › searchar.html

Searching for a Character or a Substring within a String

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.

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Navigating the String Universe: Search and Replace in Java | CodeSignal Learn

Our exploration begins with a string search. Java provides the indexOf() and lastIndexOf() methods.

medium.com › @AlexanderObregon › checking-if-a-string-contains-a-word-or-phrase-in-java-08ef51495d87

Checking if a String Contains a Word or Phrase in Java

June 16, 2025 - The other is built into Java’s regular expression tools. The cleanest way to level the field is to convert both strings to lowercase or uppercase. That way, case stops being part of the equation. You just compare letters without case getting in the way. String message = "Scheduled System Check"; String search = "system"; boolean match = message.toLowerCase(Locale.ROOT).contains(search.toLowerCase(Locale.ROOT)); // true

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Java String indexOf() - Find Character Index | Vultr Docs

December 17, 2024 - The indexOf() method in Java is a powerful tool used to find the position of a specific character or substring within a string. This function returns the index within the calling String object of the first occurrence of the specified value, ...

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String Search in Java (using the JDK-API)

October 10, 2016 - Java uses a naive string searching algorithm, to determine the position of a match. Naive means that the text is processed character by character, looking for a match with the first character of the pattern. After encountering the first character match a new subroutine is started, comparing ...

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Lesson 13 - Java Tutorial - Searching A String For A Substring - YouTube

This is just a few minutes of a complete course. Get full lessons & more subjects at: http://www.MathTutorDVD.com.

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geeksforgeeks.org › java › java-string-contains-method-example

Java String contains() Method with Example - GeeksforGeeks

July 11, 2025 - In this example, we check if a specific substring is present in the given string. ... // Java Program to demonstrate working contains() method class Gfg { public static void main(String args[]) { String s = "My name is GFG"; System.out.println(s.contains("GFG")); System.out.println(s.contains("geeks")); } }