Java -- Regular Expression-simply finding numbers in strings, java -- Regular Expression
import org.junit.Test;import java.util.regex.Matcher;import java.util.regex.Pattern;public class RegexTest { @Test public void test(){ String line = "This order was placed for QT3000! OK?"; String pattern = "\\d+"; // Create a Pattern object Pattern r = Pattern.compile(pattern); // Now create matcher object. Matcher m = r.matcher(line); if (m.find( )) { System.out.println("Found value: " + m.group() ); } else { System.out.println("NO MATCH"); } }}
\ D + matches one or more numbers.
The output result is 3000.
The following is a regular expression metacharacter Syntax:
Subexpression |
Matched |
^ |
Match the beginning of a line |
$ |
Match the end of a row |
. |
Match any single character except the linefeed. You can also use the m option to allow it to match the linefeed. |
[...] |
Match any single character in the brackets. |
[^...] |
Match any single character that is not in parentheses. |
\ |
Start of the entire string |
\ Z |
End of the entire string |
\ Z |
The end of the entire string, except the end character of the last line |
Re * |
Matches 0 or more pre-expression events |
Re + |
Match one or more previous events |
Re? |
Matches 0 or 1 items before expressing the event |
Re {n} |
Match a specified n predicate events |
Re {n ,} |
Match n or more pre-expression events |
Re {n, m} |
Events are expressed before matching at least n m pieces |
A | B |
Match a or B |
(Re) |
Regular Expression group match text memory |
(? : Re) |
No regular expression group matching text memory |
(?> Re) |
Matching independent modes without backtracking |
\ W |
Match word characters |
\ W |
Match non-word characters |
\ S |
Match spaces. Equivalent to [\ t \ n \ r \ f] |
\ S |
Match non-space characters |
\ D |
Match a number. It is equivalent to [0-9]. |
\ D |
Match non-Numbers |
\ |
Start of matching string |
\ Z |
Matches the end of the string. If a new row exists, it matches the previous row. |
\ Z |
Match the end of a string |
\ G |
Match where the last match ends |
\ N |
Return reference capture group number "N" |
\ B |
Match the word boundary if it is not in parentheses. Match the backspace key in brackets |
\ B |
Match non-word boundary |
\ N, \ t, etc. |
Match line breaks, carriage returns, tabs, etc. |
\ Q |
Start of the referenced character and end with \ E |
\ E |
End reference starting with \ Q |