evaluate if array has any items in ruby

Is there a better way to declare this?

if current_user.received_replies.unread.count > 0

What I'm trying to do is match condition only if there's at least one unread object.

---

unless current_user.received_replies.unread.empty?
  # ...
end

或者，如果你的if有else ，切换个案（因为unless/else是地狱般的）：

if current_user.received_replies.unread.empty?
  # ...
else
  # ...
end

---

I'd use:

if current_user.received_replies.unread.any?

From the docs:

= Array.any?

(from ruby core)
=== Implementation from Enumerable
------------------------------------------------------------------------------
  enum.any? [{|obj| block } ]   -> true or false

------------------------------------------------------------------------------

Passes each element of the collection to the given block. The method returns
true if the block ever returns a value other than false or nil. If the block
is not given, Ruby adds an implicit block of {|obj| obj} (that is any? will
return true if at least one of the collection members is not false or nil.

       %w{ant bear cat}.any? {|word| word.length >= 3}   #=> true
       %w{ant bear cat}.any? {|word| word.length >= 4}   #=> true
       [ nil, true, 99 ].any?                            #=> true

---

这可能会更好一点：

unless current_user.received_replies.unread.empty?

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