is this a valid ruby syntax?

if step.include? "apples" or "banana" or "cheese"
say "yay"
end开发者_开发问答

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Several issues with your code.

step.include? "apples" or "banana" or "cheese"

This expression evaluates to:

step.include?("apples") or ("banana") or ("cheese")

Because Ruby treats all values other than false and nil as true, this expression will always be true. (In this case, the value "banana" will short-circuit the expression and cause it to evaluate as true, even if the value of step does not contain any of these three.)

Your intent was:

step.include? "apples" or step.include? "banana" or step.include? "cheese"

However, this is inefficient. Also it uses or instead of ||, which has a different operator precedence, and usually shouldn't be used in if conditionals.

Normal or usage:

do_something or raise "Something went wrong."

A better way of writing this would have been:

step =~ /apples|banana|cheese/

This uses a regular expression, which you're going to use a lot in Ruby.

And finally, there is no say method in Ruby unless you define one. Normally you would print something by calling puts.

So the final code looks like:

if step =~ /apples|banana|cheese/
  puts "yay"
end

---

The last two terms appear to Ruby as true, rather than having anything to do with the include? phrase.

Assuming that step is a string...

step = "some long string with cheese in the middle"

you could write something like this.

puts "yay" if step.match(/apples|banana|cheese/)

---

Here's a way to call step.include? on each of the arguments until one of them returns true:

if ["apples", "banana", "cheese"].any? {|x| step.include? x}

---

It's definitely not what you appear to be wanting. The include? method takes in a String, which is not what "apples" or "banana" or "cheese" produces. Try this instead:

puts "yay" if ["apples", "banana", "cheese"].include?(step)

But it's unclear from the context what step is supposed to be. If it's just the single word, then this is fine. If it can be a whole sentence, try joel.neely's answer.

---

The closest thing to that syntax that would do what you appear to want would be something like:

  if ["apples", "banana", "cheese"].include?(step)
    puts "yay"
  end

But one of the other suggestions using a regex would be more concise and readable.

---

Assuming step is an Array or a Set or something else that supports set intersection with the & operator, I think the following code is the most idiomatic:

unless (step & ["apples","banana","cheese"]).empty?
  puts 'yay'
end

---

I'll add some parentheses for you:

if (step.include? "apples") or ("banana") or ("cheese")
    say "yay"
end

(That would be why it's always saying "yay" -- because the expression will always be true.)

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Just to add another side to this...

If step is an Array (as calling include? seems to suggest) then maybe the code should be:

if (step - %w{apples banana cheese}) != step
  puts 'yay'
end