Difference between matches and equalsIgnoreCase or equals in string class

14
votes

matches: Will check if the complete string entered is equal to the value present in the string object.

equalsIgnoreCase: Ignoring the case, it checks if the string entered is equal to the value present in the string object.

equals: Case sensitive and it checks if the string entered is equal to the value present in the string object.

This is what I know about the methods, present in String class.

Are there any other differences(Am I missing any valuable differences)?

If there are no differences, then why cant matches method be removed from String class, since the functionality it puts forth can be achieved using the other above mentioned methods, appropriately.

5
javastringequals
matches works on regular expressions. - Lion
check this question - Rakesh
Sorry but am not confused between equals and equalsIgnoreCase - Anuj Balan
@Ajj:) You may be confusing about regular expressions. A regular expression provides a concise and flexible means to "match" (specify and recognize) strings of text, such as particular characters, words, or patterns of characters. Abbreviations for "regular expression" include "regex" and "regexp". In simple words, a regular expression defines a pattern that matches a certain set of strings. - Lion

5 Answers

27
votes

There is a big difference - matches checks the match of a String to a regular expression pattern, not the same string. Do not be mislead by the fact that it receives a String as an argument.

For example:

"hello".equals(".*e.*"); // false
"hello".matches(".*e.*"); // true
13
votes

The key difference is that matches matches a regular expressions whereas equals matches a specific String.

System.out.println("hello".matches(".+"));    // Output: true
System.out.println("hello".equals(".+"));     // Output: false
System.out.println("wtf?".matches("wtf?"));   // Output: false
System.out.println("wtf?".equals("wtf?"));    // Output: true

I suggest you have a look at what a regular expression is

2
votes

This is what I got from the documentation...

matches (String regex): Tells whether or not this string matches the given regular expression

equals (String Object): Compares this string to the specified object. The result is true if and only if the argument is not null and is a String object that represents the same sequence of characters as this object.

equalsIgnoreCase (String anotherString): Compares this String to another String ignoring case considerations. Two strings are considered equal ignoring case if they are of the same length and corresponding characters in the two strings are equal ignoring case.

0
votes

matches returns true if the string matches a regular expression, therefore, it should not be removed from the String class.

0
votes

matches() used for verifying---- whether the given string matches to specified regexpression

ex.;String s = "humbapumpa jim"; assertTrue(s.matches(".(jim|joe)."));

equals() for just checking the given string with specified string as exact match. equalsIgnoreCase() --- will ignore the case sensitive.