c# - regular expression to escape html entities -

i have string contains html formatting tags. using regex.replace() convert text within tags character "x" want leave tags are. string escaping tags.

as far understood question, following code solve problem:

string str = @"hi, how you. hope doing good"; regex.replace(str, @"[a-za-z0-9]", "z"); 

output:

zz, zzz zzz zzz. zzzz zzz zzz zzzzz zzzz 

if don't want replace numbers occuring in word z remove 0-9. if want other characters in words replace z include there. e.g., [a-za-z\-] include - in regex , replace z too. in regex, note match special characters, should preceded \. e.g., match [, should \[.

hope help.

update:

i got you. solution problem is:

string str = @"hi, how you. hope doing & ¥ whatis goind on &lessthan;and";             matchcollection matches = regex.matches(str, @"\b(?!&)[a-za-z]+(?!;)\b");              foreach (match m in matches)             {                 string oldword = m.tostring();                 str = regex.replace(str, oldword, regex.replace(m.tostring(), @".", "z"));              }             console.writeline(str); 

and, output is:

zz, zzz zzz zzz. zzzz zzz zzz zzzzz zzzz & ¥ zzzzzz zzzzz zz &lessthan;zzz 

note: if want use html convert/extract characters or pattern it's fine.but, if planning parse whole html using regex don't try so. because html non-regular language. , regex doesn't have capability parse html.