Regex test whether string contains digits

Question

I wanted to test if a string contains numbers (at least one number) so I tried out this:

public class Test {
private static final String DIGIT_PATTERN = "^(?=.*\\d)";
private static final Pattern DIGIT_PATTERN_COMPILED = Pattern.compile(DIGIT_PATTERN);

/**
 * 
 * @param args
 */
public static void main(String[] args) {
    String passwordOne = "123";
    String passwordTwo = "abc";

    Matcher matcher = null;

    matcher = DIGIT_PATTERN_COMPILED.matcher(passwordOne);

    if(!matcher.matches()) {
        System.out.println("Password " + passwordOne + " contains no number");
    } else {
        System.out.println("Password " + passwordOne + " contains number");
    }

    matcher = DIGIT_PATTERN_COMPILED.matcher(passwordTwo);

    if(!matcher.matches()) {
        System.out.println("Password " + passwordTwo + " contains no number");
    } else {
        System.out.println("Password " + passwordTwo + " contains number");
    }   
}
}

Unfortunately both if clauses print out that it contains no number. Am I using the regex wrong?

Please tag your question with the language (java?).

Barmar
– Barmar

2013-11-20 09:46:50 +00:00
Commented Nov 20, 2013 at 9:46 — Barmar
– Barmar, Commented Nov 20, 2013 at 9:46
What is a digital number, BTW?

devnull
– devnull

2013-11-20 09:57:19 +00:00
Commented Nov 20, 2013 at 9:57 — devnull
– devnull, Commented Nov 20, 2013 at 9:57

venite · Accepted Answer · 2013-11-20 09:59:43Z

3

The most basic pattern

".*[0-9].*"

works for me with your code.

answered Nov 20, 2013 at 9:59

venite

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2 Comments

Brooklyn99 Over a year ago

this worked for me. the \\d did not work for me

venite Over a year ago

Glad to hear it!

hsz · Accepted Answer · 2013-11-20 09:46:04Z

2

Just try with following regex:

private static final String DIGIT_PATTERN = "\\d+";

answered Nov 20, 2013 at 9:46

hsz

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4 Comments

user1882812 Over a year ago

i fount this rege: ^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=])(?=\S+$).{8,}$ and thought it is possible to just splitt it up

hsz Over a year ago

There is no need to involve this bunch of regex if you just want to check if is there \\d.

user1882812 Over a year ago

i want to check the whole regex but step by step do print out different messages when something is missing in my password. so i thought simply splitting it up would do the trick.

Brooklyn99 Over a year ago

System.out.println("200SSS".matches("\\d+")); returns false because it only looks for digits in the string, so using System.out.println("200SSS".matches(".*[0-9].*")); yields true to me because I am looking for atleast one digit in a string

SQB · Accepted Answer · 2013-11-20 09:46:44Z

1

Why not just use

private static final String DIGIT_PATTERN = "\\d";

That should match if there's any number in there.

answered Nov 20, 2013 at 9:46

SQB

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