Question

I have been trying to build a regular expression but haven’t been able to get one specific condition to work.

I want a regex to remove all non alpha characters with the exception of dash (-). Dashes should only be replaced if they are prefixed by a space.

I.e.

TEST-TEST -TEST#TEST.TEST

should be changed to

TEST-TEST TEST TEST TEST

I had been using [^a-zA-Z0-9] but haven’t been able to include one OR condition init.

Answer 1

Here is what I came up with (\s-|[^A-Za-z0-9-])… It will remove all non alphanumerics but keep the “-” except if there is a space before it ” -“

Test using sed in Linux, at the moment I don’t have access to VS or Mono to test in C#

echo "TEST-TEST -TEST#TEST.TEST -1234" | sed 's/\(\s-\|[^A-Za-z0-9-]\)/ /g'

Output

TEST-TEST TEST TEST TEST 1234

• () and | are used for the OR condition
• We first remove all ” -” using \s-
• next we keep all alphanumerics and “-” with [^A-Za-z0-9-]