lua - Lua 中的贪婪/非贪婪模式匹配和可选后缀

Question

在 Lua 中，我试图进行模式匹配和捕获:

+384 Critical Strike (Reforged from Parry Chance)

作为

(+384) (Critical Strike)

其中后缀 (Reforged from %s) 是可选的。

长版

我正在尝试匹配 Lua using patterns (i.e. strfind ) 中的字符串

Note: In Lua they don't call them regular expressions, they call them patterns because they're not regular.

示例字符串:

+384 Critical Strike
+1128 Hit

这分为我想要捕捉的两部分:

数字，带前导正负指示符；他的情况是 +384

字符串，在本例中是 Critical Strike 。

我可以使用一个相当简单的模式来捕捉这些:



lua 中的这种模式有效:

local text = "+384 Critical Strike";
local pattern = "([%+%-]%d+) (.+)";
local _, _, value, stat = strfind(text, pattern);

值 = +384

统计 = Critical Strike

棘手的部分

Now 我需要扩展正则表达式模式以包含一个可选的后缀:

+384 Critical Strike (Reforged from Parry Chance)

分为:



注意: 我不是特别关心可选的尾随后缀；这意味着我不需要捕获它，尽管捕获它会很方便。

这就是我开始遇到贪婪捕获问题的地方。马上我已经拥有的模式做了我不希望它做的事情:

模式 = ([%+%-]%d+) (.+)

值 = +384

统计 = Critical Strike (Reforged from Parry Chance)

但是让我们尝试在模式中包含后缀:



与模式:

pattern = "([%+%-]%d+) (.+)( %(Reforged from .+%))?"

我正在使用 ? 运算符来指示后缀的 0 或 1 外观，但匹配 没有 。

我盲目地尝试将可选的后缀组从括号 ( 更改为括号 [ :

pattern = "([%+%-]%d+) (.+)[ %(Reforged from .+%)]?"

但现在比赛又贪婪了:

值 = +384

统计 = Critical Strike (Reforged from Parry Chance)

基于 Lua pattern reference ):

• x: (where x is not one of the magic characters ^$()%.[]*+-?) represents the character x itself.
• .: (a dot) represents all characters.
• %a: represents all letters.
• %c: represents all control characters.
• %d: represents all digits.
• %l: represents all lowercase letters.
• %p: represents all punctuation characters.
• %s: represents all space characters.
• %u: represents all uppercase letters.
• %w: represents all alphanumeric characters.
• %x: represents all hexadecimal digits.
• %z: represents the character with representation 0.
• %x: (where x is any non-alphanumeric character) represents the character x. This is the standard way to escape the magic characters. Any punctuation character (even the non-magic) can be preceded by a '%' when used to represent itself in a pattern.
• [set]: represents the class which is the union of all characters in set. A range of characters can be specified by separating the end characters of the range with a '-'. All classes %x described above can also be used as components in set. All other characters in set represent themselves. For example, [%w_] (or [_%w]) represents all alphanumeric characters plus the underscore, [0-7] represents the octal digits, and [0-7%l%-] represents the octal digits plus the lowercase letters plus the '-' character. The interaction between ranges and classes is not defined. Therefore, patterns like [%a-z] or [a-%%] have no meaning.
• [^set]: represents the complement of set, where set is interpreted as above.

For all classes represented by single letters (%a, %c, etc.), the corresponding uppercase letter represents the complement of the class. For instance, %S represents all non-space characters.

The definitions of letter, space, and other character groups depend on the current locale. In particular, the class [a-z] may not be equivalent to %l.

和魔法匹配器:

* ，匹配类中的 0 个或多个重复字符。这些重复项将始终匹配最长的可能序列；

+ ，匹配类中的 1 个或多个重复字符。这些重复项将始终匹配最长的可能序列；

- ，它也匹配类中的 0 个或多个重复字符。与 '*' 不同，这些重复项将始终匹配最短的序列；

? ，匹配类中字符出现0次或1次；

我注意到有一个贪婪的 * 和一个非贪婪的 - 修饰符。由于我的中间字符串匹配器:

(%d) (%s) (%s)

似乎一直在吸收文本直到最后，也许我应该尝试通过将 * 更改为 - 来使其不贪婪:

oldPattern = "([%+%-]%d+) (.*)[ %(Reforged from .+%)]?"
newPattern = "([%+%-]%d+) (.-)[ %(Reforged from .+%)]?"

除了现在它无法匹配:

值 = +384

统计 = 无

而不是中间组捕获“任何”字符(即 . )，我尝试了一个包含除 ( 之外的所有内容的集合:

pattern = "([%+%-]%d+) ([^%(]*)( %(Reforged from .+%))?"

从那里车轮从马车上脱落:

local pattern = "([%+%-]%d+) ([^%(]*)( %(Reforged from .+%))?"
local pattern = "([%+%-]%d+) ((^%()*)( %(Reforged from .+%))?"
local pattern = "([%+%-]%d+) (%a )+)[ %(Reforged from .+%)]?"

我以为我很接近:

local pattern = "([%+%-]%d+) ([%a ]+)[ %(Reforged from .+%)]?"

哪个捕获

- value = "+385"
- stat = "Critical Strike "  (notice the trailing space)

所以这就是我用头撞枕头 sleep 的地方；我简直不敢相信我在这个正则表达式上花了四个小时......模式。

@NicolBolas 使用伪正则表达式语言定义的所有可能字符串的集合是:

+%d %s (Reforged from %s)

在哪里

+ 表示 Plus Sign ( + ) 或 "Minus Sign" ( - )

%d 代表任何拉丁数字字符(例如 0..9 )

%s 代表任何拉丁大写或小写字母，或嵌入的空格(例如 A-Za-z )

其余字符是文字​​。

如果我必须写一个正则表达式，显然试图做我想做的事:

\+\-\d+ [\w\s]+( \(Reforged from [\w\s]+\))?

但是如果我解释得不够好，我可以给你几乎完整的列表，列出我可能在野外遇到的所有值。

+123 Parry 正数，单字

+123 Critical Strike 正数，两个字

-123 Parry 负数，单字

-123 Critical Strike 负数，两个字

+123 Parry (Reforged from Dodge) 正数，单字，可选后缀，单字

+123 Critical Strike (Reforged from Dodge) 正数，两个字，可选后缀存在两个字

-123 Parry (Reforged from Hit Chance) 负数，单字，可选后缀存在两个字

-123 Critical Strike (Reforged from Hit Chance) 负数，两个字，可选后缀存在两个字

有 奖励 个模式，显然这些模式也匹配:

+1234 Critical Strike Chance 四位数字，三个字

+12345 Mount and run speed increase 五位数字，五个字

+123456 Mount and run speed increase 六位数字，五个字

-1 MoUnT aNd RuN sPeEd InCrEaSe 一位数，五个字

-1 HiT (Reforged from CrItIcAl StRiKe ChAnCe) 负一位数，1 个字，可选后缀为 3 个字

虽然理想的模式应该与上述奖励条目相匹配，但并非必须如此。

本土化

实际上，我试图解析的所有“数字”都将被本地化，例如:

+123,456 英语(en-US)

德国的 +123.456 (de-DE)

+123'456 法语 (fr-CA)

+123 456 爱沙尼亚语 (et-EE)

阿萨姆语的 +1,23,456 (as-IN)

任何答案都必须 而不是 试图解释这些本地化问题。您不知道将显示数字的语言环境，这就是为什么从问题中删除了数字本地化的原因。您 必须 严格假定数字包含 plus sign 、 hyphen minus 和拉丁数字 0 到 9 。我已经知道如何解析本地化数字。这个问题是关于尝试将可选后缀与贪婪模式解析器匹配。

编辑 :您真的不必尝试处理本地化数字。在某种程度上，在不知道语言环境的情况下尝试处理它们是错误的。例如，我没有包括所有可能的数字本地化。另一个:我不知道 future 可能存在哪些本地化。

Answer 1

嗯我没有安装 Lua4 但这个模式在 Lua5 下有效。我希望它也适用于 Lua4。

更新 1 :由于已经指定了附加要求(本地化)，我已经调整了模式和测试以反射(reflect)这些要求。

更新 2 :更新了模式和测试以处理包含@IanBoyd 在评论中提到的数字的附加文本类。添加了说明
的字符串模式。

更新 3 :为问题的上次更新中提到的单独处理本地化数字的情况添加了变化。

尝试:

"(([%+%-][',%.%d%s]-[%d]+)%s*([%a]+[^%(^%)]+[%a]+)%s*(%(?[%a%s]*%)?))"

或(不尝试验证数字本地化标记) - 只需取任何不是在模式末尾带有数字标记的字母:

"(([%+%-][^%a]-[%d]+)%s*([%a]+[^%(^%)]+[%a]+)%s*(%(?[%a%s]*%)?))"

以上两种模式都不是为了处理科学记数法中的数字(例如:1.23e+10)

Lua5 测试(编辑清理 - 测试变得困惑):

function test(tab, pattern)
   for i,v in ipairs(tab) do
     local f1, f2, f3, f4 = v:match(pattern)
     print(string.format("Test{%d} - Whole:{%s}\nFirst:{%s}\nSecond:{%s}\nThird:{%s}\n",i, f1, f2, f3, f4))
   end
 end

 local pattern = "(([%+%-][',%.%d%s]-[%d]+)%s*([%a]+[^%(^%)]+[%a]+)%s*(%(?[%a%s]*%)?))"
 local testing = {"+123 Parry",
   "+123 Critical Strike",
   "-123 Parry",
   "-123 Critical Strike",
   "+123 Parry (Reforged from Dodge)",
   "+123 Critical Strike (Reforged from Dodge)",
   "-123 Parry (Reforged from Hit Chance)",
   "-123 Critical Strike (Reforged from Hit Chance)",
   "+122384    Critical    Strike      (Reforged from parry chance)",
   "+384 Critical Strike ",
   "+384Critical Strike (Reforged from parry chance)",
   "+1234 Critical Strike Chance (Reforged from CrItIcAl StRiKe ChAnCe)",
   "+12345 Mount and run speed increase (Reforged from CrItIcAl StRiKe ChAnCe)",
   "+123456 Mount and run speed increase (Reforged from CrItIcAl StRiKe ChAnCe)",
   "-1 MoUnT aNd RuN sPeEd InCrEaSe (Reforged from CrItIcAl StRiKe ChAnCe)",
   "-1 HiT (Reforged from CrItIcAl StRiKe ChAnCe)",
   "+123,456 +1234 Critical Strike Chance (Reforged from CrItIcAl StRiKe ChAnCe)",
   "+123.456 Critical Strike Chance (Reforged from CrItIcAl StRiKe ChAnCe)",
   "+123'456 Critical Strike Chance (Reforged from CrItIcAl StRiKe ChAnCe)",
   "+123 456 Critical Strike Chance (Reforged from CrItIcAl StRiKe ChAnCe)",
   "+1,23,456 Critical Strike Chance (Reforged from CrItIcAl StRiKe ChAnCe)",
   "+9 mana every 5 sec",
   "-9 mana every 20 min (Does not occurr in data but gets captured if there)"}
 test(testing, pattern)

这是模式的分割:

local explainPattern =  
   "(" -- start whole string capture
   ..
   --[[
   capture localized number with sign - 
   take at first as few digits and separators as you can 
   ensuring the capture ends with at least 1 digit
   (the last digit is our sentinel enforcing the boundary)]]
   "([%+%-][',%.%d%s]-[%d]+)" 
   ..
   --[[
   gobble as much space as you can]]
   "%s*"
   ..
   --[[
   capture start with letters, followed by anything which is not a bracket 
   ending with at least 1 letter]]
   "([%a]+[^%(^%)]+[%a]+)"
   ..
   --[[
   gobble as much space as you can]]
   "%s*"
   ..
   --[[
   capture an optional bracket
   followed by 0 or more letters and spaces
   ending with an optional bracket]]
   "(%(?[%a%s]*%)?)"
   .. 
   ")" -- end whole string capture