1

nextRuby中的反义词是什么？我试图找到一个prev不存在的功能。

"b".prev会 == "a"，就像"a".next=="b"

# A grad student at a local university thinks he has discovered a formula to
# predict what kind of grades a person will get. He says if you own less than 
# 10 books, you will get a "D". If you own 10 to 20 books, you will get a "C", 
# and if you own more than 20 books, you will get a "B".
# He further hypothesizes that if you actually read your books, then you will
# get a full letter grade higher in every case.
#
# grade(4,  false)  # => "D"
# grade(4,  true)   # => "C"
# grade(15, true)   # => "B"
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1 回答 1

3

如果您的案例仅限于唯一字符，则以下内容将允许您获取上一个或下一个字符：

def next_char(c)
  (c.chr.ord + 1).chr
end

def prev_char(c)
  (c.chr.ord - 1). chr
end

puts next_char('A')
puts prev_char('B')

但是，当您处理成绩时，我会选择一种成绩枚举。例如，查看该博客文章以了解可能的实施。

参考：

于 2013-05-29T07:47:36.907 回答