Question

I would like to split a text into groups on a special character match.

For example, the following text should be divided into three parts, splitting on each m= match:

v=0 o=NNMAS 8571 287 IN IP4
t=1358416438 0
m=audio 43538 RTP/AVP 0 8 18 96 97
c=IN IP4
a=sendrecv
m=audio 43538 RTP/AVP 0 8 18 96 97
c=IN IP4

should become

1:

v=0 o=NNMAS 8571 287 IN IP4
t=1358416438 0

2:

m=audio 43538 RTP/AVP 0 8 18 96 97
c=IN IP4
a=sendrecv

3:

m=audio 43538 RTP/AVP 0 8 18 96 97
c=IN IP4

How can I achieve this?

Answer 1

The easiest way would be to split on the regex (?m)^(?=m=).

Explanation:

(?m)  # Turn on multiline mode (so the next line works correctly).
^     # Assert position at the start of the line.
(?=   # Assert that the following text can be matched at the current position:
 m=   #  m=
)     # End of lookahead assertion.

You need to tell us which regex engine you’re using so we can provide a working code sample.

In JavaScript, the mode modifiers need to go outside of the regex, so you get:

result = subject.split(/^(?=m=)/m);