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Articles by Maruthi Krishna
Page 35 of 50
Program to find whether a string is alphanumeric.
Any word that contains numbers and letters is known as alphanumeric. The following regular expression matches the combination of numbers and letters."^[a-zA-Z0-9]+$";The matches method of the String class accepts a regular expression (in the form of a String) and matches it with the current string in case the match this method returns true else it returns false.Therefore, to find whether a particular string contains alpha-numeric values −Get the string.Invoke the match method on it bypassing the above mentioned regular expression.Retrieve the result.Example 1import java.util.Scanner; public class AlphanumericString { public static void main(String args[]) { Scanner sc ...
Read MoreHow to remove consonants from a string using regular expressions in Java?
The simple character class “[ ]” matches all the specified characters in it. The meta character ^ acts as negation within the above character class i.e. the following expression matches all the characters except b (including spaces and special characters)"[^b]"Similarly, the following expression matches all the consonants in the given input string."([^aeiouyAEIOUY0-9\W]+)";Then you can remove the matched characters by replacing them with the empty string “”, using the replaceAll() method.Example 1public class RemovingConstants { public static void main( String args[] ) { String input = "Hi welc#ome to t$utori$alspoint"; String regex = "([^aeiouAEIOU0-9\W]+)"; ...
Read MoreProgram to match vowels in a string using regular expression in Java
You can group all the required characters to match within the square braces “[ ]” i.e. The metacharacter/sub-expression “[ ]” matches all the specified characters. Therefore, to match all the letters specify the vowel letters within these as shown below −[aeiouAEIOU]Example 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class MatchVowels { public static void main( String args[] ) { String regex = "[aeiouAEIOU]"; System.out.println("Enter input string: "); Scanner sc = new Scanner(System.in); String input = sc.nextLine(); //Compiling the regular expression Pattern.compile(regex); ...
Read MoreMoving all Upper case letters to the end of the String using Java RegEx
The subexpression “[ ]” matches all the characters specified in the braces. Therefore, to move all the upper case letters to the end of a string −Iterate through all the characters in the given string.Match all the upper case letters in the given string using the regular expression "[A-Z]".Concatenate the special characters and the remaining characters to two different strings.Finally, concatenate the special characters string to the other string.Example 1public class RemovingSpecialCharacters { public static void main(String args[]) { String input = "sample B text C with G upper case LM characters in between"; ...
Read MoreMoving all special char to the end of the String using Java Regular Expression RegEx)
The following regular expression matches all the special characters i.e. all characters except English alphabet spaces and digits."[^a-zA-Z0-9\s+]"To move all the special characters to the end of the given line, match all the special characters using this regex concatenate them to an empty string and concatenate remaining characters to another string finally, concatenate these two strings.Example 1public class RemovingSpecialCharacters { public static void main(String args[]) { String input = "sample # text * with & special@ characters"; String regex = "[^a-zA-Z0-9\s+]"; String specialChars = ""; String inputData ...
Read MoreWhat is difference between matches() and find() in Java Regex?
The java.util.regex.Matcher class represents an engine that performs various match operations. There is no constructor for this class, you can create/obtain an object of this class using the matches() method of the class java.util.regex.Pattern.Both matches() and find() methods of the Matcher class tries to find the match according to the regular expression in the input string. In case of a match, both returns true and if a match is not found both methods return false.The main difference is that the matches() method try to match the entire region of the given input i.e. if you are trying to search for ...
Read MorePattern asPredicate() method in Java with examples
The Predicate interface of the java.util.function package can be used as a target for lambda expressions. The test method of this interface accepts a value ad validates it with the current value of the Predicate object. This method returns true in-case of a match, else false.The asPredicate() method of the java.util.regex.Pattern class returns a Predicate object which can match a string with the regular expression using which the current Pattern object was compiled.Example 1import java.util.Scanner; import java.util.function.Predicate; import java.util.regex.Pattern; public class AsPredicateExample { public static void main( String args[] ) { //Reading string value ...
Read MorePattern DOTALL field in Java with examples
The DOTALL field of the Pattern class Enables dotall mode. By default, the “.” Meta character in regular expressions matches all characters except line terminators.Example 1import java.util.regex.Matcher; import java.util.regex.Pattern; public class DOTALL_Example { public static void main( String args[] ) { String regex = "."; String input = "this is a sample this is second line"; Pattern pattern = Pattern.compile(regex); Matcher matcher = pattern.matcher(input); int count =0; while(matcher.find()) { count++; System.out.print(matcher.group()); ...
Read MorePattern COMMENTS field in Java with examples
The COMMENTS field of the Pattern class allows whitespace and comments in pattern. When you use this as flag value to the compile() method, white spaces and, comments starting with # are ignored in the given pattern.Example 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class COMMENTES_Example { public static void main( String args[] ) { Scanner sc = new Scanner(System.in); System.out.println("Enter input data: "); String input = sc.nextLine(); //Regular expression to find digits String regex = "\d #ignore this comment"; //Compiling ...
Read MorePattern CASE_INSENSITIVE field in Java with examples
This CASE_INSENSITIVE field of the Pattern class matches characters irrespective of case. When you use this as flag value to the compile() method and if you search for characters using regular expressions characters of both cases will be matched.Note − By default, this flag matches only ASCII charactersExample 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class CASE_INSENSITIVE_Example { public static void main( String args[] ) { Scanner sc = new Scanner(System.in); System.out.println("Enter input data: "); String input = sc.nextLine(); System.out.println("Enter required character: "); char ...
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