CODEWITHSUNDEEP
javaregex
kofucii
kofucii

Reputation: 7653

Regex to match word, followed by zero or more digits?

I need a regular expression to match line beginning with a specific WORD, followed by zero or more digits, then nothing more. So far I've tried this:

^WORD\d{0,}

and this:

^WORD[0-9]*

But it doesn't work as expected: it is also matching lines like WORD11a, which I don't want.

Upvotes: 2

Views: 18320

Answers (3)

kofucii
kofucii

Reputation: 7653

I forgot the $ end of line character, so it matched:

WORD1
WORD11
WORD11a

this works, just fine:

^WORD\\d*$

Upvotes: 3

user3841723
user3841723

Reputation: 1

"(\\AWORD[\\d]*$)" this should do the trick. beginning of input, your WORD, and a number

Upvotes: 0

aioobe
aioobe

Reputation: 420951

The problem is probably that ^ matches the beginning of the input (I suspect you only find a match if the first line matches), and not the beginning of a line.

You could try using a positive lookbehind saying that the match should be preceded by either start of input (^) or a new line (\n):

String input = "hello156\n"+
               "world\n" +
               "hello\n" +
               "hell55\n";

Pattern p = Pattern.compile("(?<=^|\n)hello\\d*");
Matcher m = p.matcher(input);
while (m.find())
    System.out.println("\"" + m.group() + "\"");

Prints:

"hello156"
"hello"

Upvotes: 0

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