Replacing variable length string with some word

Question

Given the below string

Declare @string varchar(max)=\'abc ___________ deffns ___ cg _ hif _______hh ihs\';

this is the Output requi

Answer 1

In C# you can use:

string str = Regex.Replace(s, @"(_)\1{5,}", Lastname);

It will match character _ if more than 5 _ occurs.