In this article, we will discuss how to compare two strings using String’s compareToIgnoreCase() method which ignores CASE difference while comparing

1. String’s compareToIgnoreCase(String anotherString) method:

• This String method compares 2 string lexicographically ignoring CASE differences and returns an integer value
  1. Returns 0, if str1 == str2 (both strings are lexicographically equal)
  2. Returns +ve value, if str1 > str2 (1^st string lexicographically greater than 2^nd string)
  3. Returns -ve value, if str1 < str2 (1^st string lexicographically lesser than 2^nd string)
• Note: This is same as that of String’s compareTo(String anotherMethod), but it ignores CASE differences while comparing 2 strings

1.1 Method Signature:

public int compareToIgnoreCase(String anotherString);

1.2 Returns:

• Returns an integer value after lexicographical comparison

2. Examples on compareTo() method:

• Below piece of code depicts lexicographical comparison

StringCompareToIgnoreCaseMethod.java

package in.bench.resources.string.methods;

public class StringCompareToIgnoreCaseMethod {

	public static void main(String[] args) {

		String str1 = "STAR";
		String str2 = "star";
		String str3 = "OneStAR";
		String str4 = "ONEStar";

		// compare 1: lexicographically comparing ignoring CASE
		int compare1 = str1.compareToIgnoreCase(str2);

		// printing to console
		System.out.println("String comparison of str1 and str2 : "
				+ compare1);

		// compare 2: lexicographically comparing ignoring CASE
		int compare2 = str3.compareToIgnoreCase(str4);

		// printing to console
		System.out.println("String comparison of str3 and str4 : "
				+ compare2);
	}
}

Output:

String comparison of str1 and str2 : 0
String comparison of str3 and str4 : 0

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References:

• https://docs.oracle.com/javase/tutorial/essential/concurrency/immutable.html
• https://docs.oracle.com/javase/tutorial/essential/concurrency/imstrat.html
• https://docs.oracle.com/javase/tutorial/java/data/strings.html
• https://docs.oracle.com/javase/8/docs/api/java/lang/String.html
• https://docs.oracle.com/javase/8/docs/api/java/lang/class-use/String.html
• https://docs.oracle.com/javase/8/docs/api/java/lang/StringBuffer.html
• https://docs.oracle.com/javase/8/docs/api/java/lang/StringBuilder.html

Happy Coding !!
Happy Learning !!