Regular Expressions 101

Pro

Negative Lookbehind(?<!\h)

\hany horizontal whitespace character

Group 1(\h{2,})?

?repeats the group contents below at most once:

\h{2,}any horizontal whitespace character, repeated at least 2 times

$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.

25 tokens

(?<!\h)\h(\h{2,})?$

New

yes 1: 
yes 3:   
no 2:  
end.....

yes 1: 
yes 3:   
no 2:  
end.....