Regular Expressions 101

Explanation

Pro

Negative Lookbehind(?<!\S)

\Sany non-whitespace character

Positive Lookahead(?=\S{8}\s)

\S{8}any non-whitespace character, repeated exactly 8 times

\sany whitespace character

Non-Capturing Group(?:[^\s\d%]*[%\d]){3}

{3}repeats the group contents below exactly 3 times:

Negated Character Class[^\s\d%]*

*matches any number of characters outside the set below:

\sany whitespace character

\da digit

%the literal % (37₁₀ / 45₈ / 25₁₆)

Character Class[%\d]

%the literal % (37₁₀ / 45₈ / 25₁₆)

\da digit

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

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.

26 tokens

(?<!\S)(?=\S{8}\s)(?:[^\s\d%]*[%\d]){3}\S*

New

this word ab1d2f3h needs to go, but not this word abcdefgh %%%

ab1d2f3h 
ab%d2f3h 
ab%d%f3h 
ab%d%f%h 

ab%d%fh 
ab%d%f%hh 
ab%d%fjh

this word ab1d2f3h needs to go, but not this word abcdefgh %%%

ab1d2f3h 
ab%d2f3h 
ab%d%f3h 
ab%d%f%h 

ab%d%fh 
ab%d%f%hh 
ab%d%fjh