Regular Expressions 101

Explanation
Pro

\ban ASCII word boundary

Negative Lookahead(?!(\D\S*|[12][0-9]{3})\b)

Group 1(\D\S*|[12][0-9]{3})

1st Alternative\D\S*

\Dany character that's not a digit

\S*any non-whitespace character, repeated any number of times

2nd Alternative[12][0-9]{3}

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-9]{3}

{3}matches exactly 3 characters from the set below:

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\ban ASCII word boundary

\S+any non-whitespace character, repeated at least once

\ban ASCII word boundary

Global pattern flags

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

Detailed match information will be displayed here automatically.

25 tokens

\b(?!(\D\S*|[12][0-9]{3})\b)\S+\b

New

foo bar 12 3.4 32 1992 112 0433 3312 182470921358 3,412 some text

foo bar 12 3.4 32 1992 112 0433 3312 182470921358 3,412 some text