编辑:
我最初的问题是询问匹配整个单词的速度是否比正则表达式还要快.我添加了我的代码，并运行了一些测试.详细信息如下
My original question was asking whether anything could ever be faster than regex for matching a whole word. I have added my code, and have run several tests. The details are below
我的示例匹配字符串(来自老人与海)
My sample matching string (from The Old Man And The Sea)
他是一个老人，独自一人在墨西哥湾流中的一条小艇上钓鱼，现在他已经八十四天没有钓鱼了.在最初的四十天里，有一个男孩和他在一起.但是在四十天没吃鱼之后，男孩的父母告诉他，现在肯定是老人了，最后是萨拉sal，这是最不幸的一种形式，男孩顺着他们的命令去了另一条船，第一条船抓了三条好鱼.周
这是我的正则表达式
"(\b(cod|tuna|mackerel|plaice|haddock|salmon|prawns|shrimp|fishcake|halibut|sole|eel|anchovy|anchovies|sardine|herring|bonito|whiting|seabass|carp|crab|flounder|pollock|mullet|ray|ray wings|clam|mussel|scallop)(s?)\b)"这是我第一次不使用正则表达式的匹配尝试
Here's my first matching attempt without regex
public static words = "cod|tuna|mackerel|plaice|haddock|salmon|prawns|shrimp|fishcake|halibut|sole|eel|anchovy|anchovies|sardine|herring|bonito|whiting|seabass|carp|crab|flounder|pollock|mullet|ray|ray wings|clam|mussel|scallop"; public static bool MatchBySplitting(string sentence) { string[] sentence_words = sentence.Split(',','.',' ',';','-'); string[] match_words = words.Split('|'); foreach(string w in sentence_words) { foreach(string m in match_words) { if(m == w) return true; } } return false; }每次运行5000次迭代:
Running 5000 iterations of each:
- 正则表达式匹配: 250-300毫秒
- MatchBySplitting :250-350毫秒，与正则表达式可比.
- Regex Matching: 250-300 ms
- MatchBySplitting: 250-350 ms, a comparable time to the regex.
但是，如果我将匹配的字符串缩短到第一行，我的结果就会改变
However, if I shorten my matching string to just the first line, my results change
他是一个老人，独自一人在墨西哥湾流的一条小艇中捕鱼，现在已经走了八十四天了，没有捞到鱼.
regex保持不变，但是MatchBySplitting加快了很多速度:
The regex stays about the same, but MatchBySplitting speeds up a lot:
- 正则表达式匹配:220-260毫秒
- MatchBySplitting :50-150毫秒-比正则表达式快.
- Regex Matching: 220-260 ms
- MatchBySplitting: 50-150 ms - Faster than regex.
如果我随后开始混淆经典，并插入一个将匹配的单词
If I then start messing with the classics, and insert a word that will match
他是一个老人，独自一人在墨西哥湾流中的一条小艇上钓鱼，现在他已经八十四天没有钓鱼了.然后在第五八十天，他抓到了一条金枪鱼.结束
- 正则表达式匹配:170-300毫秒
- MatchBySplitting :100-200毫秒-比正则表达式快.
- Regex Matching: 170-300 ms
- MatchBySplitting: 100-200 ms - Faster than regex.
我想我已经在这里回答了我自己的问题.在大多数情况下，我的自定义匹配方法似乎等于或快于正则表达式.
I think I've answered my own question here. My custom matching method seems to be equal to or faster than regex in most cases.
但是，我没有在代码中涵盖所有单词边界(！?)，因此如果在其中添加这些单词，可能会稍微放慢速度.
However, I haven't covered all word boundaries in my code (!?) so it may slow down a little if I add those in.
推荐答案尝试制作一个已编译的正则表达式，如下所示:
Try making a compiled regex, like this:
static readonly Regex CornRegex = new Regex("\b(corn)\b", RegexOptions.Compiled);这实际上将生成并编译一个方法，该方法包含匹配该正则表达式所需的汇编指令.它应该非常快，可以与编写自己的遍历各个字符的自定义函数相媲美.
This will actually generate and compile a method that contains the assembly instructions needed to match that regex. It should be very fast, comparable to writing your own custom function that loops over the individual characters.
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有没有比正则表达式更快的单词匹配整个单词?
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