JAVA REGEX extract round colon “123:32:21”

Question

Here's the string format I'm working with: 123:23:21

The three separate numbers could range from 1 to 99999, it's essentially a key to represent a set of data.

I need to extract each of the separate numbers

• The first before the colon "123"
• The second between the first colon "32" and last colon
• The third after the last colon "21"

I've found a few answers (below), but don't provide enough info for a complete amateur to do what I need too.

• Regular expression to match word pairs joined with colons
• Regex to find a string after the last colon
• Regex: Question mark and colon

These are completely wrong but I've tried variations of ^\\w+:$ , ^:\\w+:$ , ^:\\w+$ .

Can anyone give me a heads up as to how to implement this in Java? Could be regex or substring.

Answer 1

In java, u can use split method of String or can use Scanner.useDelimiter(pattern)

Ex-

String str = "123:23:21";
String[] nums = str.split(":");

num[0] - 123, num[1] = 23, num[2] = 21 //output

Answer 2

Get rid of the ^ and $ , as these, respectively, indicate the start and end of the string.

Try just \\w+ (the : can be omitted since \\w doesn't include : , and wouldn't work too well at the start and end of the string, unless you make it optional).

Then you'll use Matcher.find() to find each occurrence.

Answer 3

This will help you to match the number from 1 - 99999 separated by colon.

String input = "text 123:23:99999 number";
Pattern pattern = Pattern.compile("(?:\\D|^)([1-9][0-9]{0,4}):([1-9][0-9]{0,4}):([1-9][0-9]{0,4})(?:\\D|$)");
Matcher m = pattern.matcher(input);
if (m.find()) {
    System.out.println(m.group(1));
    System.out.println(m.group(2));
    System.out.println(m.group(3));
}

Answer 4

You can split() -

String string = "123:23:21";
String[] parts = string.split(":");
for(String p:parts){
    System.out.println(p);
}
/* OUTPUT */
123
23
21

Answer 5

For the string 123:32:21 You can use [^:]+: to get 123: and :[^:]+: to get :32: and :[^:]+ to get :21 and the remove the : from the string

A nice explanation for regex is give in http://www.beedub.com/book/2nd/regexp.doc.html

Answer 6

First of all \\w matches word chatacters. For only numbers you need \\d. You can extract all three numbers with one regexp using matching groups.

(\d+)\:(\d+)\:(\d+)

Dont forget to write double backslashes if you init your Pattern. From a Matcher which is created by your Pattern you then get the group data. Groups are the ( ) areas from your regexp.

You could improve this by ^ and $ like you already did to force line boundaries.