CODEWITHSUNDEEP
c#regex
Ice
Ice

Reputation: 303

Matching a string in regex

This is the string that I want to match:

"t=0, data=00 00 00 f1 00 00 00 00".

The following works:

The following doesn't work:

Here is my code at the moment : 

Regex rgx = new Regex(@"^(t)=[0-9]+,\s\w+=((\s[0-9A-F-a-f]{2}){8})");
if(rgx.IsMatch(line.Trim())){
  //...
}

Upvotes: 1

Views: 207

Answers (4)

errieman
errieman

Reputation: 1949

^(t)=[0-9]+,\s\w+=([0-9A-Fa-f]{2}(\s|$)){8} will do the trick. you placed a whitespace character after each two digits, but because the last two digits don't have a whitespace after them the regex won't match. Now the regex engine can choose between a whitespace character or an end of string.

Edit: changed word boundary to end of string

Edit2: also, take a look at this: http://www.regular-expressions.info/anchors.html

Upvotes: 1

Boris the Spider
Boris the Spider

Reputation: 61178

Okay, to match the pattern:

t=0, data=00 00 00 f1 00 00 00 00

I have made some assumptions:

  • there can be any number of digits following t=
  • there are 8 groups of two hex digits following the data=
  • you need the data in a match group

Then this pattern will work:

^t=[0-9]++,\s*+data=(?<data>(?:[0-9a-f]{2}\s?){8})$

A test in Java

public static void main(String[] args) throws SQLException {
    final String data = "t=0, data=00 00 00 f1 00 00 00 00";
    final Pattern pattern = Pattern.compile("^t=[0-9]++,\\s*+data=(?<data>(?:[0-9a-fA-F]{2}\\s?){8})$");
    final Matcher matcher = pattern.matcher(data);
    if (matcher.matches()) {
        System.out.println(matcher.group());
        System.out.println(matcher.group("data"));
    }
}

Output:

t=0, data=00 00 00 f1 00 00 00 00
00 00 00 f1 00 00 00 00

Upvotes: 0

Rakhitha
Rakhitha

Reputation: 328

for (\s[0-9A-F-a-f]{2}) to match first pair of digits just after = sign you need to have a space between the = sign and first digit. But it seems you dont.

Also is (\s[0-9A-F-a-f]{2}) correct?. I think you need to delete the '-' between F and a.

Upvotes: 0

Hugo Dozois
Hugo Dozois

Reputation: 8420

If I understand well your needs you could use the following regex :

Regex rgx = new Regex(@"(^t=[0-9]+,[a-z ]+=([A-Fa-f0-9]{2} ?){8})");
if(rgx.IsMatch(line.Trim())){
    //...
}

So:

  • ^t=[0-9]+,[a-z ]+= matches everything before the hex numbers.
  • ([A-Fa-f0-9]{2} ?){8} matches 8 groups of 2 hex character followed or not by a space.

Everything is included in the $1 variable as the enclosing parenthesis matches the full line.

Upvotes: 1

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