如何使用条件运算符(?:)红宝石?

ternary operator

if_this_is_a_true_value ? then_the_result_is_this : else_it_is_this

if if a then b else c end a ? b : c

puts (if 1 then 2 else 3 end) # => 2

puts 1 ? 2 : 3                # => 2

x = if 1 then 2 else 3 end
puts x                        # => 2

puts if 1

question = if question.size > 20 then
  question.slice(0, 20) + "..."
else 
  question
end

puts true ? "true" : "false"
=> "true"


puts false ? "true" : "false"
=> "false"

truncate

<% question = truncate(question, :length=>30) %>

(true) ? 1 : 0

\

(true)   \
  ? 1    \
  : 0

(true) ?
  1 :
  0

..

true

<% question = question.size > 20 ? question.question.slice(0, 20)+"..." : question.question %>

<% question = (question.size > 20) ? question.question.slice(0, 20)+"..." : question.question %>

<% question = (question.size > 20) ? question.question.slice(0, 20) + "..." \
                                   : question.question 
%>

<% question = if (question.size > 20)
                question.question.slice(0, 20) + "..."
              else 
                question.question 
              end
%>

question.question

player_id=1
....
player_id==1? enemy_id=2 : enemy_id=1
# => enemy=2

post

condition ? statement_A : statement_B

if condition == true
  statement_A
else
  statement_B
end