Return Value. 4. It's mid-way between the using a regular expression and using toLowerCase on the entire search string: the search string needs to be over about 60 characters before the regular expression was faster. prefix or enable the case insensitive flag directly in the Pattern.compile().. A regex pattern example. Java Regular Expression :split 2: 15. This method returns a negative integer, zero, or a positive integer as the specified String is greater than, equal to, or less than this String, ignoring case considerations. In a Java program, you want to determine whether a String contains a case-insensitive regular expression (regex). List Of Regular Expression Sample Programs: Simple regex pattern matching using string matches(). Java String FAQ: How can I tell if a Java String contains a given regular expression (regex) pattern? Method to check if a String contains a sub string ignoring case in Java; Check if a string contains only alphabets in Java using Regex; How do we check if a String contains a substring (ignoring case) in Java? Since the Java regular expressions are case sensitive by default they did not match with our pattern which has all the lower case letters.. Solution: Use the String matches method, and include the magic (?i:X) syntax to make your search case-insensitive. int compareToIgnoreCase(String str) Parameters. You don't want to manipulate the String or extract the match, you just want to determine whether the pattern exists at least one time in the given String. The contains() method of the String class accepts Sting value as a parameter, verifies whether the current String object contains the specified String and returns true if it does (else false).. Split a String into a Java Array of Strings divided by an Regular Expressions: 12. The reason is two “second” words have the first character in capital letters. Strip extra spaces in a XML string: 17. How to extract a group from a Java String that contains a Regex pattern; How to test if a string contains specific words in Java? Remove trailing white space from a string: 18. Syntax. How to replace a pattern using regular expression in java? Example Here is the detail of parameters − str − the String to be compared. To enable the regex case insensitive matching, add (?) The string against which we evaluated our expression has a “second” word 3 times, but the pattern only matched once. Java regex with case insensitive. Case Insensitive Matching. Compares this String to another String, ignoring case considerations. Java Regular Expression : Split text: 14. 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. Simple java regex using Pattern and Matcher classes. Two characters c1 and c2 are considered the same ignoring case if … Get all digits from a string: 16. Problem: In a Java program, you want to determine whether a String contains a pattern, you want your search to be case-insensitive, and you want to use String matches method than use the Pattern and Matcher classes.. In Java, by default, the regular expression (regex) matching is case sensitive. 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. Here is the syntax of this method − public boolean equalsIgnoreCase(String anotherString) Parameters. The problem with that though is that there is no "NoCase" type methods built into the Java string (except for String::equalsIgnoreCase(), but that doesn't use regular expressions). Regular Expression Replace: 13. Use Pattern class directly and compile it with Pattern.CASE_INSENSITIVE flag. How to validate IP address using regular expression? String matches() perform case sensitive matching. The toLoweCase() method of the String class converts all the characters in the current String into lower case and returns.. To find whether a String contains a particular sub string irrespective of case − If you want case insensitive matching, there are two options.