Parameter:
regex -- the regular expression to which this string is to be matched.Return Value:
This method returns true if, and only if, this string matches the given regular expression.Example:
public class TestRegex {
public static void main(String args[]){
String Str = new String("Welcome to pritomkumar.blogspot.com");
System.out.print("Contains 'pritom': " );
System.out.println(Str.matches("(.*)pritom(.*)"));
System.out.print("Starts with 'Welcome': " );
System.out.println(Str.matches("Welcome(.*)"));
System.out.print("Ends with '.com': " );
System.out.println(Str.matches("(.*).com"));
System.out.print("Starts with small characters: " );
System.out.println(Str.matches("[a-z](.*)"));
System.out.print("Starts with cap characters: " );
System.out.println(Str.matches("[A-Z](.*)"));
System.out.print("Starts with digits: " );
System.out.println(Str.matches("[0-9](.*)"));
}
}
OUTPUT:
Contains 'pritom': true
Starts with 'Welcome': true
Ends with '.com': true
Starts with small characters: false
Starts with cap characters: true
Starts with digits: false
Table 1. Common matching symbols
Regular Expression | Description |
---|---|
. | Matches any character |
^regex | regex must match at the beginning of the line |
regex$ | Finds regex must match at the end of the line |
[abc] | Set definition, can match the letter a or b or c |
[abc][vz] | Set definition, can match a or b or c followed by either v or z |
[^abc] | When a "^" appears as the first character inside [] when it negates the pattern. This can match any character except a or b or c |
[a-d1-7] | Ranges, letter between a and d and figures from 1 to 7, will not match d1 |
X|Z | Finds X or Z |
XZ | Finds X directly followed by Z |
$ | Checks if a line end follows |
Table 2: Meta-characters
Regular Expression | Description |
---|---|
\d | Any digit, short for [0-9] |
\D | A non-digit, short for [^0-9] |
\s | A whitespace character, short for [ \t\n\x0b\r\f] |
\S | A non-whitespace character, for short for [^\s] |
\w | A word character, short for [a-zA-Z_0-9] |
\W | A non-word character [^\w] |
\S+ | Several non-whitespace characters |
\b | Matches a word boundary. A word character is [a-zA-Z0-9_] and \b matches its bounderies. |
Regular Expression | Description | Examples |
---|---|---|
* | Occurs zero or more times, is short for {0,} | X* - Finds no or several letter X, .* - any character sequence |
+ | Occurs one or more times, is short for {1,} | X+ - Finds one or several letter X |
? | Occurs no or one times, ? is short for {0,1} | X? -Finds no or exactly one letter X |
{X} | Occurs X number of times, {} describes the order of the preceding liberal | \d{3} - Three digits, .{10} - any character sequence of length 10 |
{X,Y} | Occurs between X and Y times, | \d{1,4}- \d must occur at least once and at a maximum of four |
*? | ? after a quantifier makes it a reluctant quantifier, it tries to find the smallest match. |