Regular Expressions 101

Positive Lookbehind(?<=key)

keythe literal text key (case sensitive)

\sa Unicode whitespace character

Non-Capturing Group(?:\d+[\s,]+)+

+repeats the group contents below at least once:

\d+a Unicode decimal digit, repeated at least once

Character Class[\s,]+

+matches at least one character from the set below:

\sa Unicode whitespace character

,the literal , (44₁₀ / 54₈ / 2C₁₆)

Non-Capturing Group(?:and )?

?repeats the group contents below at most once:

and the literal text and (case sensitive)

\d+a Unicode decimal digit, repeated at least once

Global pattern flags

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?<=key)\s(?:\d+[\s,]+)+(?:and )?\d+

New

some text key 12, 32, 311 ,465 and 345. some other text dog 612, 
12, 32, 9 and 10. some text key 1, 2.

a key is dog 3242342342, 345345