Regular Expressions 101

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/
^(?<date>[^\s]+) (?<time>[^\s]+) - (?<message>.*)$
/
^ asserts position at start of the string
Named Capture Group date
(?<date>[^\s]+)
Match a single character not present in the list below
[^\s]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
matches the character with index 3210 (2016 or 408) literally (case sensitive)
Named Capture Group time
(?<time>[^\s]+)
Match a single character not present in the list below
[^\s]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
-
matches the characters - literally (case sensitive)
Named Capture Group message
(?<message>.*)
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
$ asserts position at the end of the string, or before the line terminator right at the end of the string (if any)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/

Test String