How To Check If A String Contains A Particular Substring In Java
Chapter:
String Handling
Last Updated:
22-08-2023 17:19:49 UTC
Program:
/* ............... START ............... */
// Using String.contains() Method:
String mainString = "Hello, world!";
String substring = "world";
boolean containsSubstring = mainString.contains(substring);
if (containsSubstring) {
System.out.println("Substring found!");
} else {
System.out.println("Substring not found.");
}
// Using String.indexOf() Method:
String mainString = "Hello, world!";
String substring = "world";
int index = mainString.indexOf(substring);
if (index != -1) {
System.out.println("Substring found at index " + index);
} else {
System.out.println("Substring not found.");
}
// Using Regular Expressions (Pattern and Matcher):
import java.util.regex.Pattern;
import java.util.regex.Matcher;
String mainString = "Hello, world!";
String regex = "world";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(mainString);
if (matcher.find()) {
System.out.println("Substring found!");
} else {
System.out.println("Substring not found.");
}
// Using Java 8+ Stream API:
String mainString = "Hello, world!";
String substring = "world";
boolean containsSubstring = mainString.chars()
.mapToObj(c -> String.valueOf((char) c))
.collect(Collectors.joining())
.contains(substring);
if (containsSubstring) {
System.out.println("Substring found!");
} else {
System.out.println("Substring not found.");
}
/* ............... END ............... */
Notes:
-
Using String.contains() Method: The String class in Java provides a method called contains() that can be used to check if a string contains a specified substring.
- Using String.indexOf() Method: The indexOf() method returns the index of the first occurrence of a specified substring within the string. If the substring is not found, it returns -1.
- Using Regular Expressions (Pattern and Matcher): If you need more complex pattern matching, you can use regular expressions with the Pattern and Matcher classes.
- Using Java 8+ Stream API: If you are using Java 8 or later, you can use the Stream API to check if a string contains a substring.
- Choose the method that best suits your needs based on the complexity of the substring search you're performing. The first two methods are simpler and sufficient for most cases, while the regular expression approach and Stream API approach offer more flexibility for advanced scenarios.
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How to check if a string contains a particular substring in java #Java Program to Check if a string contains a substring