Question

validates_format_of            :order_of_importance, :on => :create, :with => /^[1-3]{3}$/,
                             :message => "Order of Importance must have 3 Digits"

现在我已经验证使用的数字是1, 2, 3，但我想也确保不仅使用这些数字，而且每个数字仅用于一次。

例如：

应该是工作号码

2 3 1

1 3 2

1 2 3

不应该是有效的数字：

1 1 2

2 2 1

3 3 3

Answer 1

if subject =~ /\A(?:\A(?=[1-3]{3}\Z)(\d)(?!\1)(\d)(?!(?:\1|\2))\d\Z)\Z/
    # Successful match
else
    # Match attempt failed
end

这将匹配一个字符串，其中包含1-3个范围内的3个数字，没有重复的数字。

细分：

"
^              # Assert position at the beginning of the string
(?=            # Assert that the regex below can be matched, starting at this position (positive lookahead)
   [1-3]          # Match a single character in the range between “1” and “3”
      {3}            # Exactly 3 times
   \$              # Assert position at the end of the string (or before the line break at the end of the string, if any)
)
(              # Match the regular expression below and capture its match into backreference number 1
   \\d             # Match a single digit 0..9
)
(?!            # Assert that it is impossible to match the regex below starting at this position (negative lookahead)
   \\1             # Match the same text as most recently matched by capturing group number 1
)
(              # Match the regular expression below and capture its match into backreference number 2
   \\d             # Match a single digit 0..9
)
(?!            # Assert that it is impossible to match the regex below starting at this position (negative lookahead)
   (?:            # Match the regular expression below
                     # Match either the regular expression below (attempting the next alternative only if this one fails)
         \\1             # Match the same text as most recently matched by capturing group number 1
      |              # Or match regular expression number 2 below (the entire group fails if this one fails to match)
         \\2             # Match the same text as most recently matched by capturing group number 2
   )
)
\\d             # Match a single digit 0..9
\$              # Assert position at the end of the string (or before the line break at the end of the string, if any)
"

Answer 2

检查所有3个是不是更容易！有效的排列？

编辑：

但要接受挑战： (?:1(?!\d*1)|2(?!\d*2)|3(?!\d*3)){3}

它使用negative lookaheads来确保只挑选一次数字。

编辑：

Checked with rubular.com

Answer 3

你可以将字符串分成3个数字。 a，b和c。

然后你有很多方法可以检查。 e.g。

min val == 1 and max == 3 and sum = 6

将3放入一组（我希望ruby具有set集合类型），集合的大小应为3。

等。

正则表达式可能不是解决此问题的最佳工具。

Answer 4

正如其他人已经说过的，最好使用方法或其他方法来检查唯一性。但是如果你有理由使用正则表达式，那么正则表达式看起来就像这样

^(\d)\s*(?!\1)(\d)\s*(?!\1|\2)(\d)$

它在每个数字上使用否定前瞻，通过检查已捕获的组来确认重复。如果你只需要检查1,2和3，那么你可以使用这个

^([123])\s*(?!\1)([123])\s*(?!\1|\2)([123])$

Answer 5

我强烈推荐[在线正则表达式构建器] [1]

[1]：http://www.gskinner.com/RegExr/以避免怀疑

如何验证一系列唯一数字？

5 个答案: