Pattern matching using Regex in Java

Question

I have a stream from which I read a string that looks like the following:

event.tag.report tag_id=0xABCD0029605, type=ISOB_80K, antenna=1, frequency=918250, rssi=-471, tx_power=330, time=2017-12-18T19:44:07.198
                        ^^^^^^^^^^^^^

I am trying to use Regex to just get the highlighted part (underlined by ^^^^) for every string that I read. My pattern for the Regex is as follows:

.*\\s(tag_id=)(.{38})(\\,\\s)(.*)$

However, this does not work for tag_ids which are longer than or shorter than 38 digits.

Can someone help me with a string pattern that will help me just get the highlighted area in the string independent of its size?

sprinter · Accepted Answer · 2017-12-19 02:40:29Z

1

Looks to me as though you want all hexidecimal characters:

"tag_id=(0x[A-F0-9]+)"

So

Pattern pattern = Pattern.compile("tag_id=(0x[A-F0-9]+)");
Matcher matcher = pattern.matcher("event.tag.report tag_id=0x313532384D3135374333343435393031, type=ISOC");
if (matcher.find())
    System.out.println(matcher.group(1));

returns:

0x313532384D3135374333343435393031

edited Dec 19, 2017 at 2:40

answered Dec 19, 2017 at 0:56

sprinter

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4 Comments

Sagar Nair Over a year ago

Hey, this seems to work only partially I am unable to get the entire string before the ,. if my String has tag_id=0x313532384D3135374333343435393031 then it only outputs tag_id=0x313532384D313537.

sprinter Over a year ago

@SagarNair Not for me. I added my test code and it works fine. Are you sure you don't have a hidden character after the 7?

Sagar Nair Over a year ago

can you please try this string

event.tag.report tag_id=0x3504B40180019F112A05F6EB, type=ISOC, antenna=2, frequency=918250, rssi=-638, tx_power=330, time=2017-12-18T20:17:02.865

. I am sorry I know I can too but its not working for me. Thanks :)

sprinter Over a year ago

@SagarNair yes that works fine. Altered the code to demonstrate. Note that I changed matches for find because the pattern matches a part of the input, not the entire input.

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