The following should be matched:
AAA123
ABCDEFGH123
XXXX123
can I do: ".*123"
?
Yes that will work, though note that .
will not match newlines unless you pass the DOTALL flag when compiling the expression:
Pattern pattern = Pattern.compile(".*123", Pattern.DOTALL);
Matcher matcher = pattern.matcher(inputStr);
boolean matchFound = matcher.matches();
There are lots of sophisticated regex testing and development tools, but if you just want a simple test harness in Java, here's one for you to play with:
String[] tests = {
"AAA123",
"ABCDEFGH123",
"XXXX123",
"XYZ123ABC",
"123123",
"X123",
"123",
};
for (String test : tests) {
System.out.println(test + " " +test.matches(".+123"));
}
Now you can easily add new testcases and try new patterns. Have fun exploring regex.
.*
and.+
are for any chars except for new lines.
Just in case, you would wanted to include new lines, the following expressions might also work for those languages that double escaping is required such as Java or C++:
[\\s\\S]*
[\\d\\D]*
[\\w\\W]*
for zero or more times, or
[\\s\\S]+
[\\d\\D]+
[\\w\\W]+
for one or more times.
Double escaping is not required for some languages such as, C#, PHP, Ruby, PERL, Python, JavaScript:
[\s\S]*
[\d\D]*
[\w\W]*
[\s\S]+
[\d\D]+
[\w\W]+
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegularExpression{
public static void main(String[] args){
final String regex_1 = "[\\s\\S]*";
final String regex_2 = "[\\d\\D]*";
final String regex_3 = "[\\w\\W]*";
final String string = "AAA123\n\t"
+ "ABCDEFGH123\n\t"
+ "XXXX123\n\t";
final Pattern pattern_1 = Pattern.compile(regex_1);
final Pattern pattern_2 = Pattern.compile(regex_2);
final Pattern pattern_3 = Pattern.compile(regex_3);
final Matcher matcher_1 = pattern_1.matcher(string);
final Matcher matcher_2 = pattern_2.matcher(string);
final Matcher matcher_3 = pattern_3.matcher(string);
if (matcher_1.find()) {
System.out.println("Full Match for Expression 1: " + matcher_1.group(0));
}
if (matcher_2.find()) {
System.out.println("Full Match for Expression 2: " + matcher_2.group(0));
}
if (matcher_3.find()) {
System.out.println("Full Match for Expression 3: " + matcher_3.group(0));
}
}
}
Full Match for Expression 1: AAA123
ABCDEFGH123
XXXX123
Full Match for Expression 2: AAA123
ABCDEFGH123
XXXX123
Full Match for Expression 3: AAA123
ABCDEFGH123
XXXX123
If you wish to explore the expression, it's been explained on the top right panel of regex101.com. If you'd like, you can also watch in this link, how it would match against some sample inputs.
jex.im visualizes regular expressions:
Specific Solution to the example problem:-
Try [A-Z]*123$
will match 123
, AAA123
, ASDFRRF123
. In case you need at least a character before 123
use [A-Z]+123$
.
General Solution to the question (How to match "any character" in the regular expression):
[\w|\W]{min_char_to_match,}
.[\S]{min_char_to_match,}
.