在Ruby中交换字符串中的字母

Question

我需要使用Ruby和以下规则交换字符串（DNA链）中的字母：

• 'A'已被'T'
取代
• 'T'已被'A'
取代
• 'C'已被'G'
取代
• 'G'已被'C'
取代

例如，'ACGTA'应该变为'TGCAT'。

我只有这么远：

def DNA_strand(dna)    
  dna.tr!('A', 'T')    
end

Answer 1

你很亲密：

dna.tr('ATCG', 'TAGC')   # => "TGCAT"

请参阅ruby-doc.org on tr：

  

返回str的副本，其中from_str中的字符替换为to_str   tr!中的相应字符。

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