Describe all the string comparison methods available in java with examples

Describe all the string comparison methods available in java with examples.

Answer:-

String Comparison Methods in Java

Java provides several methods to compare String values. These methods can compare based on content, lexicographical order, or case-insensitive equality.

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1. equals(String anotherString)

• Compares content of two strings.
• Case-sensitive.

String s1 = "Java";
String s2 = "Java";
System.out.println(s1.equals(s2));  // true

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2. equalsIgnoreCase(String anotherString)

• Compares content ignoring case.

String s1 = "Java";
String s2 = "java";
System.out.println(s1.equalsIgnoreCase(s2));  // true

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3. compareTo(String anotherString)

• Lexicographically compares strings.
• Returns:
  • 0 if both are equal,
  • < 0 if s1 < s2,
  • > 0 if s1 > s2

String s1 = "Apple";
String s2 = "Banana";
System.out.println(s1.compareTo(s2));  // Negative value

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4. compareToIgnoreCase(String anotherString)

• Same as compareTo() but ignores case.

String s1 = "apple";
String s2 = "Apple";
System.out.println(s1.compareToIgnoreCase(s2));  // 0

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5. startsWith(String prefix)

• Checks if string starts with the given prefix.

String s = "HelloWorld";
System.out.println(s.startsWith("Hello"));  // true

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6. endsWith(String suffix)

• Checks if string ends with the given suffix.

String s = "HelloWorld";
System.out.println(s.endsWith("World"));  // true

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7. contains(CharSequence seq)

• Checks if string contains the given sequence.

String s = "Learning Java";
System.out.println(s.contains("Java"));  // true

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8. regionMatches(...)

• Compares a specific region (substring) of two strings.

String s1 = "HelloWorld";
String s2 = "World";
System.out.println(s1.regionMatches(5, s2, 0, 5));  // true

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9. matches(String regex)

• Compares using regular expressions.

String s = "abc123";
System.out.println(s.matches("[a-z]+\\d+"));  // true

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Summary Table

Method	Case Sensitive	Purpose
equals()	Yes	Content equality
equalsIgnoreCase()	No	Content equality
compareTo()	Yes	Lexicographic comparison
compareToIgnoreCase()	No	Lexicographic comparison
startsWith()	Yes	Starts with prefix
endsWith()	Yes	Ends with suffix
contains()	Yes	Contains sequence
regionMatches()	Optional	Region-wise comparison
matches()	Yes	Pattern match using regex