Regex that matches anything except a specific string

[Richard Anderson]

I am trying to feed a regular expression to a mail processing program that
matches every string except a specific string. For example, I want a regex
that does not match (e-mail address removed) but matches any other
string. If I were writing a Perl program, I would just do this:

if ($address !~ /^richard\@richard-anderson\.org$/) { print "Spam\n" }

but I am not able to modify the source code of the program I am using.

I haven't been able to do this using the complement metacharacter (^). I'd
accept a solution that matches anything except an anagram of
(e-mail address removed)

P.S. This is actually a Python regex, but Python's regexes are very similar
to Perl's regexes.

 

[Dave Oswald]

I am trying to feed a regular expression to a mail processing program that
matches every string except a specific string. For example, I want a regex
that does not match (e-mail address removed) but matches any other
string. If I were writing a Perl program, I would just do this:

if ($address !~ /^richard\@richard-anderson\.org$/) { print "Spam\n" }

but I am not able to modify the source code of the program I am using.

I haven't been able to do this using the complement metacharacter (^). I'd
accept a solution that matches anything except an anagram of
(e-mail address removed)

P.S. This is actually a Python regex, but Python's regexes are very similar
to Perl's regexes.

Your question has nothing to do with Perl, and the Perlish solution won't
work for Python unless Python's regexp is identical to Perl's. "Very
similar" isn't close enough.

That said, in Perl you would write a regexp to look like this:
/^(?!richard\@richard-anderson\.org)$/

That's a negative lookahead assertion.

 

[Jeff 'japhy' Pinyan]

I am trying to feed a regular expression to a mail processing program that
matches every string except a specific string. For example, I want a regex
that does not match (e-mail address removed) but matches any other
string. If I were writing a Perl program, I would just do this:

if ($address !~ /^richard\@richard-anderson\.org$/) { print "Spam\n" }

but I am not able to modify the source code of the program I am using.

I don't usually answer non-Perl questions in this newsgroup, but I'll
pretend you're asking how to turn

if ($str !~ /^pat$/) { ... }

into a match using =~ instead.

if ($str =~ /^(?!richard\@richard-anderson\.org$)/) { ... }

 

[Bill]

I am trying to feed a regular expression to a mail processing program that
matches every string except a specific string. For example, I want a regex
that does not match (e-mail address removed) but matches any other
string. If I were writing a Perl program, I would just do this:

if ($address !~ /^richard\@richard-anderson\.org$/) { print "Spam\n" }

but I am not able to modify the source code of the program I am using.

I haven't been able to do this using the complement metacharacter (^). I'd
accept a solution that matches anything except an anagram of
(e-mail address removed)

P.S. This is actually a Python regex, but Python's regexes are very similar
to Perl's regexes.

Though I don't know if python supports them, look at zero-with
look-ahead, NEGATIVE assertions, for example,

/^.?(?!richard\@richard-anderson\.org)/