迭代數組，修改並插入其他元素

Question

我想迭代一個數組，修改其元素基於一個標準，並希望在每個元素之後插入另一個元素，除了最後一個元素之外。什麼是最通俗的Ruby方式呢？

def transform(input) 
    words = input.split 
    words.collect {|w| 
    if w == "case1" 
     "add that" 
    else 
     "add these" + w 
    end 
    # plus insert "x" after every element, but not after the last 
    } 
end 

實施例：

transform("Hello case1 world!") => ["add theseHello", "x", "add that", "x", "add theseworld!"] 

Answer 1

製作大約期望的輸出一些假設，和編輯工作：

def transform(input) 
    input.split.inject([]) do |ar, w| 
    ar << (w == "case1" ? "add that" : "add these" + w) << "x" 
    end[0..-2] 
end 

p transform("Hello case1 world!") 

#=> ["add theseHello", "x", "add that", "x", "add theseworld!"] 

Answer 2

def transform input 
    input.split.map do |w| 
    [ 
     if w == 'case1' 
     'add that' 
     else 
     'add these' + w 
     end, 
     'x' 
    ] 
    end.flatten[0..-2] 
end 

這將常常被寫爲：

def transform input 
    input.split.map do |w| 
    [ w == 'case1' ? 'add that' : 'add these' + w, 'x' ] 
    end.flatten[0..-2] 
end