Question

This line gives me a syntax error:

if @array.include?('cat') && not @array.include?('dog')

Any ideas?

Answer 1

Do this:

if @array.include?('cat') && ! @array.include?('dog')

! and not do mostly the same thing but can’t quite be used interchangeably.

For the curious: There is actually some sort of quirk in the ruby parser that makes it unable to interpret expressions like this one, even though they are theoretically parseable and sound.

These can be parsed:

not true && true
true && not(true)

but these cannot:

true && not true
true && not (true)

Note that last one is different only in the extra space before (!