Regular Expressions 101

Pro

Non-Capturing Group(?:^if TYPE_CHECKING:\R|\G(?!\A)^[^\S\r\n]*(?: from .*)?(?:\R|$))

1st Alternative^if TYPE_CHECKING:\R

^start of line

if TYPE_CHECKING:the literal text if TYPE_CHECKING: (case sensitive)

\Ra newline sequence

2nd Alternative\G(?!\A)^[^\S\r\n]*(?: from .*)?(?:\R|$)

\Gstart of current search

Negative Lookahead(?!\A)

\Astart of string

^start of line

Negated Character Class[^\S\r\n]*

*matches any number of characters outside the set below:

\Sany non-whitespace character

\ra carriage return (ASCII 13)

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

Non-Capturing Group(?: from .*)?

?repeats the group contents below at most once:

from the literal text from (case sensitive)

.*any character (except for line terminators), repeated any number of times

Non-Capturing Group(?:\R|$)

1st Alternative\R

\Ra newline sequence

2nd Alternative$

$end of line

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.

27 tokens

(?:^if TYPE_CHECKING:\R|\G(?!\A)^[^\S\r\n]*(?: from .*)?(?:\R|$))

New

if TYPE_CHECKING:
    from foo import bar
    from x import y

if TYPE_CHECKING:
    from foo import bar
    from x import y