Question

I have an output of a command that basically lists a bunch of key/value pairs inside of it. The output is in no obvious format, therefore I think regex will be the best approach.

Output: http://pastebin.com/Hfu4nP3M

Basically, I need to store the key/value pairs (comma seperated) from lines 21-30 and store them in a map.

Is it possible to do this using regex?

Thanks.

Answer 1

I am not sure if that is what you want, but since you said that you need to store the key/value pairs (comma seperated) from lines 21-30 which are

 {memory,
     [{total,38751504},
      {processes,13711212},
      {processes_used,13711198},
      {system,25040292},
      {atom,662409},
      {atom_used,653371},
      {binary,287088},
      {code,18209655},
      {ets,1358504}]},

I assumed that you want to read values after memory that are stored inside [...].

To do this you can use something like

//creating reader to get data from file
BufferedReader in = new BufferedReader(new InputStreamReader(
        new FileInputStream("data.txt")));// file with your data

StringBuilder sb = new StringBuilder();
String line = null;
while ((line = in.readLine()) != null) {
    sb.append(line.trim());// also remove unnecessary tabulators and
                            // spaces
}
in.close();

String data = sb.toString();

Pattern pattern = Pattern.compile("\\{memory,\\[(.*?)\\]");
Matcher m = pattern.matcher(data);
if (m.find()) {
    Pattern keyValuePattern = Pattern.compile("\\{(\\w*?),(\\d*?)\\}");
    Matcher matcher = keyValuePattern.matcher(m.group(1));
    while (matcher.find())
        System.out.println(matcher.group(1) + "->" + matcher.group(2));
} else
    System.out.println("not found");

Output

total->38751504
processes->13711212
...