Multiple repeated groups pattern matching in Java

Question

Here is the question and required solution:
1.First Case:

String str = "Variable_1 in the range 0...4";

Solution: var1 = Variable_1 Range = 0...4

 Pattern p1 = Pattern.compile("(.*[^.]) in the range of (.*[^.])$");
    Matcher m1 = p1.matcher(desc);

    if (m1.find()) {
        System.out.println(m1.group(1));
        System.out.println(m1.group(2));
    }

2.Second Case:

String str = "Variable_1 in the range 0...4 Variable_2 in the range 10...40";

Solution: var1 = Variable_1 range1 = 0...4 var2 = Variable_2 range2 = 10...40

3.Third Case:

String str = "Variable_1 in the range 0...4 Variable_2 in the range 10...40 Variable_3 in the range 10...50";

Solution: var1 = Variable_1 range1 = 0...4 var2 = Variable_2 range2 = 10...40 var3 = Variable_3 range3 = 10...50

The first case works fine with the regex. I need to extend the same regex for the second and third cases. It should also be able to handle for n number of cases.

Wiktor Stribiżew · Accepted Answer · 2020-05-16 11:34:44Z

1

Assuming the of in your pattern is redundant, you may use

(\w+) in the range (\d+\.+\d+)

Or, if your strings contain of, then add it, (\w+) in the range of (\d+\.+\d+). \w+ will match one or more letters, digits or underscores. \d+\.+\d+ matches 1+ digits, 1+ dots, 1+ digits.

See the regex demo

Java demo:

String lines[]  = {"Variable_1 in the range 0...4",
    "Variable_1 in the range 0...4 Variable_2 in the range 10...40",
    "Variable_1 in the range 0...4 Variable_2 in the range 10...40 Variable_3 in the range 10...50"
};
Pattern p = Pattern.compile("(\\w+) in the range (\\d+\\.+\\d+)");
for(String line : lines)
{
    System.out.println(line);
    Matcher m = p.matcher(line);
    List<String> res = new ArrayList<>();
    while(m.find()) {
        System.out.println(m.group(1));
        System.out.println(m.group(2));
    }
}

Output:

Variable_1 in the range 0...4
Variable_1
0...4
Variable_1 in the range 0...4 Variable_2 in the range 10...40
Variable_1
0...4
Variable_2
10...40
Variable_1 in the range 0...4 Variable_2 in the range 10...40 Variable_3 in the range 10...50
Variable_1
0...4
Variable_2
10...40
Variable_3
10...50

answered May 16, 2020 at 11:34

Wiktor Stribiżew

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1 Comment

Geeky Over a year ago

Further down the line if I have to break the range part to min and max, how does the pattern look like? For example: -10...10, -32768...32767, -3.2...3.2, 0...10

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