How to Use Java String Class equalsIgnoreCase() Method

Function Description

The Java String class equalsIgnoreCase() method is used to compare the string with the specified string. It is case insensitive during the comparison. It returns boolean true/false value. Both strings will be equal if they are of the same length and corresponding characters in both the strings are the same, irrespective of the case (lowercase/uppercase).

For Example: If you have 3 String objects str1, str2 and str3 with values respectively “example”, “EXAMPLE” and “Example”, Then all objects’ values are said to be equal by this function, because all have the same length and same sequence of characters.

// string in lowercase

String str1 = "example";

// string in uppercase

String str2 = "EXAMPLE";

// string in camelcase

String str3 = "Example";

Method Signature

public boolean equalsIgnoreCase(String anotherString)

Parameter

anotherString : another string to be compared with existing string.

Return Type

The Return Type is boolean, true if passing another String have the same length and same sequence of characters irrespective case of the character(s).

Example of Java String Class equalsIgnoreCase() Method

package com.java.test;
 
public class ExampleStringEqualIgnoreCase {

    private void areStringsEqualsInIgnoreCase(String stringParam) 

{

          // string in lowercase

          String str1 = "example";

          // string in uppercase

          String str2 = "EXAMPLE";

          // string in camelcase

          String str3 = "Example";
 
          // Both strings are in lowercase, check for equality

          System.out.println("Both strings are in lowercase.  check if both are equal : " +  stringParam.equalsIgnoreCase(str1));
 
          // One string in lowercase and one in uppercase. check equality
         
 System.out.println("One string in lowercase and one in uppercase.check if both are equal : " + stringParam.equalsIgnoreCase(str2));
 

          // One string in lowercase and one in camelcase. check equality

          System.out.println("One string in lowercase and one in camelcase. check if both are equal : " + stringParam.equalsIgnoreCase(str3));
 
    }
 
    public static void main(String[] args) {

          String str = "example";

          ExampleStringEqualIgnoreCase example = new 
ExampleStringEqualIgnoreCase();

          System.out.println("//check strings equality by equalsIgnoreCase ");
        
  example.areStringsEqualsInIgnoreCase(str);
   
    }
 
}
 

Output:

//check strings equality by equalsIgnoreCase

Both strings are in lowercase. check if both are equal : true

One string in lowercase and one in uppercase.check if both are equal : true

One string in lowercase and one in camelcase. check if both are equal : true

Other Methods of String Class

SequenceMethodDescription
1char charAt(int index)This method is used to return the character of the string at specified index. First character is at index 0 while last is at string length-1 . StringIndexOutOfBounds Exception is thrown if valid index value is not passed.
2int length()Returns the number of characters count  in  a string.
3static String format(String format, Object… args)Return the formatted String. It is a static method and formats the string as per passing format and argument(s).
4static String format(Locale l, String format, Object… args)Return the formatted String. It is a static method and formats the string as per passing format and argument(s) and locale.
5String substring(int beginIndex)Returns substring from the given index position to the end index of the string.
6String substring(int beginIndex, int endIndex)Returns substring from the specified begin index to the specified end index.
7boolean contains(CharSequence s)Returns boolean value(true/false). It searches the given sequence of characters within the string and returns true/false accordingly. Characters will be case sensitive while searching in string.
8static String join(CharSequence delimiter, CharSequence… elements)Returns joined string. This method joins each passing String using the specified delimiter. It is a static method.
9static String join(CharSequence delimiter, Iterable<? extends CharSequence> elements)Returns the joined string. This method joins each passing string object of an iterate object using the specified delimiter and returns the concatenated string. It is a static method.
10boolean equals(Object another)Returns boolean value(true/false). It checks the equality of string with the passing object.
11boolean isEmpty()Returns boolean value(true/false). It returns true if the string is empty otherwise returns false.
12String concat(String str)Returns the concatenating string. It concatenates the passing string at the end of the string.
13String replace(char old, char new)Return the replaced string. It replaces all occurrences of the specified character with the new character.
14String replace(CharSequence old, CharSequence new)Return the replaced string. It replaces all occurrences of the specified Character sequence with the specified new Character sequence.
15String replaceAll(String regex, String replacement)Returns the replaced string. It replaces all occurrences of the sequence of characters with the given replacement string that are matching with the given regular expression.
16String replaceFirst(String regex, String replacement)Returns the replaced string. It replaces the first matching sequence of characters with the replacement string that matches with the given regular expression.
17String[] split(String regex)Returns the array of strings resulting from splitting of the string     around matches of the given regular expression. String is breaked into strings from all  the matching regular expressions.
18String[] split(String regex, int limit)Returns the array of strings resulting from splitting of the string     around matches of the given regular expression. It breaks the string from all the matching regular expression upto the given limit.
19String intern()Returns an interned string. This method helps to compare two objects using == operator and checks in a string constant pool. it is faster for comparison.
20int indexOf(int ch)Returns the index value of first occurrence of the specified character within the string
21int indexOf(int ch, int fromIndex)Returns the index value of first occurrence of the specified character from the substring starting from specified index
22int indexOf(String substring)Returns the index value of first occurrence of the specified substring within the string.
23int indexOf(String substring, int fromIndex)Returns the index value of the first occurrence of the specified string within the substring starting from specified index to end of the string index.
24int lastIndexOf(int ch)Returns the index value of last occurrence of the specified character
25int lastIndexOf (int ch, int fromIndex)Returns the index value of last occurrence of the specified character, search starts at given fromIndex. 
26int lastIndexOf (String str)Returns the index value of last occurrence of the specified string.
27int lastIndexOf (String str, int fromIndexReturns the index value of last occurrence of the specified string, searches start from given fromIndex
28String toLowerCase()Returns all the characters of the string in lowercase .
29String toLowerCase(Locale l)Returns all the characters of the string in lowercase using specified locale.
30String toUpperCase()Returns all the characters of the string in uppercase.
31String toUpperCase(Locale l)Returns all the characters of the string in uppercase using specified locale.
32String trim()Returns the string after removing the white space from the beginning and end of the string.
33static String valueOf(int value)Return the converted string. It converts the objects and all primitive types of values into string. It is a static method.

In this article, we learned all about the equlasIgnoreCase() method of String class with examples. Apart from equlasIgnoreCase() method we got an idea about other String methods too. We will come up with more articles explaining other String methods with examples. For more details please click on the respective methods link.

This article was written by Renu Singh

14+ Years of experience in various phases of the software development life cycle. Specialties: Java/J2EE, Struts, Hibernate, JSF, JSP, Servlets, AJAX, Oracle, Oracle Knowledge, SQL Server 2000, DB2, EJB3.0. Companies Worked For: 1) Tata Consultancy Services 2) Infogain 3) TS Infotech 4) Daffodil Software Ltd.

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