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  • [Ruby] Last Index
    coding for food 2022. 8. 6. 10:25

    Write a method last_index that takes in a string and a character. The method should return the last index where the character can be found in the string.

    def last_index(str, char)
    
    end
    
    puts last_index("abca", "a")       #=> 3
    puts last_index("mississipi", "i") #=> 9
    puts last_index("octagon", "o")    #=> 5
    puts last_index("programming", "m")#=> 7
    # my code
    
    def last_index(str, char)
      word = str.split("")
      updateidx = 0
      word.each.with_index do |spell, idx|
        if spell == char
          updateidx = idx
        end
      end
    
      return updateidx
    end
    
    puts last_index("abca", "a")       #=> 3
    puts last_index("mississipi", "i") #=> 9
    puts last_index("octagon", "o")    #=> 5
    puts last_index("programming", "m")#=> 7
    # solution
    
    def last_index(str, char)
      i = str.length - 1
      while i >= 0
        if str[i] == char
          return i
        end
        i -= 1
      end
    end
    
    puts last_index("abca", "a")       #=> 3
    puts last_index("mississipi", "i") #=> 9
    puts last_index("octagon", "o")    #=> 5
    puts last_index("programming", "m")#=> 7
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