Regular Expressions 101

Pro

(?s)applies the following effective flags to the remainder of the pattern: gms

s modifier: single line. Allows a dot to match line terminators

\Astart of string

Key1:the literal text Key1: (case sensitive)

\na line-feed (newline) character (ASCII 10)

Group Key1(?P<Key1>.*)

.*any character, repeated any number of times

Key2:the literal text Key2: (case sensitive)

\na line-feed (newline) character (ASCII 10)

Group Key2(?P<Key2>.*?)

.*?any character, repeated any number of times

Non-Capturing Group(?:OptionalKey3:\n(?P<OptionalKey3>.*))?

?repeats the group contents below at most once:

OptionalKey3:the literal text OptionalKey3: (case sensitive)

\na line-feed (newline) character (ASCII 10)

Group OptionalKey3(?P<OptionalKey3>.*)

.*any character, repeated any number of times

\zend of string

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

25 tokens

(?s)\AKey1:\n(?P<Key1>.*)Key2:\n(?P<Key2>.*?)(?:OptionalKey3:\n(?P<OptionalKey3>.*))?\z

New

Key1:
  SomeValue1
  MoreValue1
Key2:
  SomeValue2
  MoreValue2
OptionalKey3:
  SomeValue3
  MoreValue3